How to Add a Border Under a Header in Microsoft Word

To add a line under a header in Word, open the header, click in the paragraph you want the line beneath, then choose Home > Paragraph > Borders > Bottom Border. The border follows the paragraph across the text area, creating a clean separator between the header and the document body. You can change its color, thickness, and position afterward.

What You’ll Need

A document open in Microsoft Word. These instructions use Word for Microsoft 365 on Windows; the Mac steps are noted where the menus differ.
A header already in place, or permission to edit the document’s header. If the document is protected, you may need the owner to allow editing first.
Optional: a preferred line color or thickness if you want something other than the default border.

Step-by-Step

Open the header. Double-click in the top margin of the page, in the area above the main document text. Word opens the header for editing and displays the Header & Footer tab. Alternatively, choose Insert > Header > Edit Header. If your header already contains a title, logo, or page number, leave those elements in place; you will add the border to a paragraph in the header, not replace the content.
Choose the paragraph that should sit above the line. Click inside the header paragraph whose bottom edge should have a border. Usually, this is the paragraph containing the header text. The border is a paragraph-formatting feature, so clicking in the paragraph is enough; you do not need to highlight every character. If the header uses several lines and you want the line below all of them, click in the last paragraph, not the first one.
Apply a bottom border. Go to the Home tab. In the Paragraph group, open the arrow beside the Borders button, then select Bottom Border. In some ribbon layouts the Borders button is shown as a small square grid; hover over it to confirm its name. A line should appear along the bottom of the paragraph. This is a paragraph border, rather than a line typed with underscore characters or a shape floating on the page.
Check which paragraph received the line. Look at the full header, especially if it contains more than one line. The border should be immediately beneath the intended text or content. If it appears too high, click in the paragraph below the one currently bordered and apply Bottom Border there instead. If the header has a spare empty paragraph at the bottom, that paragraph can create a noticeable gap, so remove it or adjust its spacing if needed.
Customize the border if the default is not suitable. Click back inside the bordered paragraph and open Home > Paragraph > Borders. Choose Borders and Shading to open the formatting dialog. On the Borders tab, choose a line style, color, and width, then make sure the preview shows the bottom edge turned on. Set Apply to to Paragraph, and choose OK. The dialog gives you more control than the one-click Bottom Border command.
Adjust the space around the line if necessary. The border sits at the paragraph boundary. To change the gap between the header text and the line, select the paragraph and use Home > Paragraph dialog launcher, then adjust paragraph spacing before or after. Keep the change modest: large spacing can make the header look detached from the page. You can also adjust the header’s distance from the top edge through Layout > Page Setup dialog launcher > Layout tab > Header, if the whole header needs to move.
Close the header and inspect the page. Select Header & Footer > Close Header and Footer, or double-click in the document body. Check that the line is visible and that it does not overlap the text below. Use Print Layout view and, if the document will be printed or shared, open print preview to confirm the result at page size.
Check other pages and sections. Scroll through the document to see whether the line appears where expected. By default, headers are linked across pages within a section, so a border added to a standard header usually appears on every page in that section. Documents can have separate first-page headers, odd and even headers, or multiple sections with unlinked headers; those areas may need the border added separately.

On a Mac: Double-click the header area, click in its paragraph, and use the Home tab’s Borders menu to choose Bottom Border. The ribbon layout can vary slightly by Word version and window size. For detailed formatting, open the Borders and Shading dialog from the Borders menu and set the border for the paragraph.

Common Mistakes

Drawing a line instead of applying a border. A shape may look right at first, but it can move when text or margins change. A paragraph bottom border stays attached to the header paragraph, which is usually more dependable for a simple divider.
Applying the border to the wrong paragraph. Word adds the bottom edge to the paragraph containing the cursor. If the cursor is in a blank paragraph, the line may appear lower than the header text. Click in the paragraph you actually want to border and apply the command again.
Expecting a border around selected words only. Bottom Border is not an underline. It runs along the paragraph’s bottom edge and can extend beyond the words toward the text margins. For a line just beneath individual characters, use underline formatting instead, though that generally is not the best choice for a page-wide header divider.
Forgetting separate header types. Selecting Different First Page or Different Odd & Even Pages creates distinct header areas. A border in one may not automatically appear in the others. Also check section breaks: a section header can be unlinked from the previous section.
Adding the border to a table cell or shape unintentionally. Some designed headers use tables, text boxes, or images. Clicking in a table cell and applying a paragraph border may not create a full-width line. Identify how the header is built before changing its borders.
Making the line too heavy or dark. A thick border can compete with the title and make every page feel crowded. Start with a thin, neutral line and check it at normal page size rather than judging only from a zoomed-in view.

Tips

Use the formatting dialog for consistency. If you need a specific shade or width, set it in Borders and Shading rather than repeatedly clicking the default border. The preview helps you confirm that only the bottom edge is active; turn off other edges if you see a box around the paragraph.
Keep the line aligned with the document text. A paragraph border normally follows the paragraph’s indentation and text boundaries. If the header has a left or right indent, the line may not span the width you expect. Check paragraph indentation in Home > Paragraph before trying to reposition the line.
Use a table border when the header is built as a table. If the title and logo sit in separate cells, a bottom border on the whole table may be more consistent than borders on individual cell paragraphs. Click inside the table, open the table layout or table design controls, and apply the bottom border to the intended table or cells. The exact contextual tab names can vary by Word version.
Make a small test before changing a long document. Apply the border on one page, inspect the first page and a later page, and then adjust the style. This is especially useful in documents with multiple sections or different first-page settings.
Use undo if the wrong edge appears. Press Ctrl+Z on Windows or Command+Z on Mac immediately after the unwanted change, then click in the correct paragraph and try again. Undo is safer than stacking extra borders while trying to remove the first one.

Troubleshooting

The border does not appear: Confirm that you are editing the header rather than the body, and that the cursor is inside a paragraph. Reopen the Borders menu and choose Bottom Border. If the text is in a table or text box, try the relevant table or shape border controls instead. Also check that the border color is not white and the width is not extremely thin in Borders and Shading.
The border appears in the wrong place: It is probably attached to a different paragraph than intended. Click in the paragraph that should directly precede the line and apply Bottom Border. If a blank paragraph follows the header text, check whether that empty paragraph is the one carrying the border.
The line stops short of the page width: Paragraph borders respect paragraph indentation and may be limited by the header’s layout. Check left and right paragraph indents. If the header uses columns, a table, or a text box, the border may be limited to that component; apply a border to the full table or adjust the component width if that is the intended design.
The line appears on some pages but not others: Look for different first-page or odd/even header settings in the Header & Footer tab. Then inspect section breaks and the Link to Previous setting. Edit the relevant header directly, or link it to the preceding section if that matches the document design; linking can also copy other header content, so check the result before closing.
The line is separated from the header by a large gap: Check paragraph spacing, empty paragraphs, and the header’s distance from the top of the page. Reduce unnecessary spacing rather than dragging the line, because the line is tied to paragraph formatting.
The line vanishes in print preview: Reopen Borders and Shading and select a visible color and a practical width. Confirm the printer or PDF preview is showing the correct page and that the line is not outside the printable area. If it remains absent, check whether the header is inside a text box or another object that has its own formatting.

Frequently Asked Questions

Does the border go across the whole page?
A paragraph bottom border usually runs across the paragraph’s available width, not necessarily the full physical page. Margins, indents, columns, and containers such as tables affect its length.

Will the line appear on every page?
It normally repeats wherever that same header is used within its section. Different first-page or odd/even headers and unlinked section headers can have separate formatting, so check each header type used in the document.

Can I change the border color and thickness?
Yes. Open Home > Paragraph > Borders > Borders and Shading, choose the line style, color, and width, and confirm the preview shows a bottom edge. Set the application target to Paragraph.

How do I remove the line?
Click inside the bordered header paragraph, open the Borders menu, and choose No Border. That removes paragraph borders from that paragraph; if other edges were intentionally applied there, you may need to set the desired edges again.

Can I put a border under a header image or logo?
Yes, but the best method depends on the layout. If the image sits in a paragraph by itself, a paragraph bottom border may work. If it is in a table or text box, use the table’s or object’s border controls so the line aligns with the complete header layout.

Is a bottom border the same as an underline?
No. An underline follows text characters, while a bottom border belongs to the whole paragraph and can extend beyond the text. For a separator beneath a header across the text area, a paragraph border is generally the more flexible choice.

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