How to Add a Line Under a Header in Microsoft Word

To add a line under text in a Word page header, double-click the header area, click in the paragraph containing the text, then choose Home > Paragraph > Borders > Bottom Border. This places a rule beneath the header paragraph and is usually the simplest way to get a clean line that follows the text as it moves. If you mean a title or heading in the main document rather than the page header, the same paragraph-border method works there too.

The steps below are for Microsoft Word for Microsoft 365 on Windows. The Mac ribbon has the same basic border feature, though its placement can vary slightly with the window size and ribbon layout. Save the document before making formatting changes, especially if it has carefully designed headers or multiple sections.

What You’ll Need

A Word document that you can edit. If it is in Protected View, select Enable Editing first if you trust the file.
Access to the header area: you can open it by double-clicking near the top of a page, or by choosing Insert > Header > Edit Header.
Optional: a preferred line color, weight, or style, if you want something other than the default thin rule.

Step-by-Step

Open the header. Scroll to a page where the header is visible and double-click in the blank area at the top of the page. Word switches to header-editing mode and displays the Header & Footer tab. You can also use Insert > Header > Edit Header. If the text you want to underline is a heading in the body of the document, do not open the page header; click in that heading instead.
Place the cursor in the header paragraph. Click anywhere in the paragraph that contains the header text. You do not usually need to select the words: a paragraph border is applied to the whole paragraph. If the header has text on separate lines or in separate paragraphs, click in the specific paragraph that should have the line. Check that the cursor is not in a nearby table cell or a separate text box, because those can have their own border controls.
Open the Borders menu. Select the Home tab. In the Paragraph group, find the Borders button, which typically looks like a small square grid. Select the arrow beside it to open its menu. If the ribbon is collapsed or the Word window is narrow, maximize the window or expand the ribbon to make the Paragraph controls easier to find.
Apply the bottom border. In the Borders menu, choose Bottom Border. A horizontal line should appear below the paragraph. It normally extends across the paragraph’s available width, not just the length of the words. That is useful for a conventional document header because the rule creates a clear visual boundary across the page.
Check the result on the page. Click Close Header and Footer on the Header & Footer tab, or double-click in the body of the document. Look at the page in Print Layout and check that the rule sits below the text, is not too close to it, and does not overlap any content. If the header is repeated, inspect another page as well.
Adjust the line if needed. Reopen the header and click in the same paragraph. Use the Borders menu to access Borders and Shading if that option is available in your Word build. In the dialog, choose a line style, color, and width, then use the preview diagram to turn on only the bottom edge. Set Apply to to Paragraph, then select OK. The preview matters: clicking a different edge can add a top, side, or full box border instead.
Choose whether it should appear on every page. By default, a header is repeated through its section. If you have different first-page or odd-and-even headers, the line may not appear in every header variant. With the header open, check the options on the Header & Footer tab, including Different First Page and Different Odd & Even Pages. Add the bottom border separately to each header paragraph where you want it.

Mac note: In Word for Mac, double-click the header, click in its paragraph, then use the Home tab and the Borders control in the Paragraph area to choose Bottom Border. Depending on the ribbon layout, you may need to expand the Paragraph group or use the Borders drop-down arrow. To leave header editing, select Close Header and Footer or double-click in the document body. The exact dialog layout can differ from Windows, but the goal is the same: apply only a bottom paragraph border.

Common Mistakes

Adding a border to the wrong paragraph. If the cursor is in a blank paragraph above or below the header text, Word puts the line there instead. Click inside the actual text paragraph and check the page again.
Choosing a full border instead of a bottom border. The default Borders button can apply whichever border was used most recently. Open its menu and explicitly choose Bottom Border, rather than clicking the main button without checking the selection.
Expecting the rule to match the words’ exact length. Paragraph borders span the paragraph area, which may be the full width between the margins. For a short line directly under a short heading, a drawn line or a bottom border on a narrow text box may be more suitable.
Forgetting that headers can differ by section or page. A document can have section breaks, a special first page, or separate odd and even headers. One line may therefore appear on some pages but not others. Inspect each header type that the document uses.
Using repeated hyphens as the final design. Typing several hyphens or underscores can create uneven-looking text, and Word may automatically convert certain character sequences into a border. Use a paragraph border or a line shape when you want consistent alignment and control.

Tips

Use a paragraph border for a standard document rule. It stays connected to the header paragraph and generally adjusts with the paragraph’s width. This is a good choice for reports, letters, resumes, and other documents where a simple full-width separator is appropriate.
Use a shape when you need precise placement. If the line should be shorter than the text area, angled, or positioned independently, choose Insert > Shapes > Line, then drag where you want it. Hold Shift while dragging on Windows to keep the line horizontal. On Mac, hold Shift while drawing for a straight horizontal or vertical line. A shape can move separately from the header text, so check its position after editing the document.
Keep the style restrained. A thin solid rule is usually easier to read than a thick or decorative border. In Borders and Shading, use the preview to confirm the edge and review the document at normal zoom before choosing a strong color or weight.
Check the print layout, not just the editing view. Headers sit within the page’s top margin area. If the line seems too close to the page edge or body text, adjust the header position or page margins using the layout controls rather than dragging the line randomly.
Make a reusable design with styles or a template. If you need the same header treatment in future documents, save a copy as a Word template after checking the header, margins, and page variants. This prevents having to recreate the formatting each time.

Troubleshooting

The line appears above the text or in the wrong place: The border was probably applied to a neighboring paragraph. Reopen the header, click directly in the paragraph with the text, and select Home > Paragraph > Borders > Bottom Border. If there are empty paragraphs in the header, turn on formatting marks with Home > Paragraph > Show/Hide ¶ to see which paragraph is selected. You can then remove the border from the unwanted paragraph through the Borders menu.

The line does not appear: Confirm you are editing the header and not the body, and make sure the cursor is in the text paragraph. Try reopening the Borders menu and selecting Bottom Border explicitly. If it still is not visible, check the line color and width in Borders and Shading; a white color or extremely fine line can disappear against the page. Also check whether you are looking at a first-page or alternate-page header that has different content.

The line is too long, too short, or misaligned: A paragraph border follows the paragraph’s width and indentation. Review the paragraph alignment and indentation on the Home tab. If you need a line of a specific length, insert a line shape and use the on-screen guides to position it, or resize a text box that holds the header. Avoid using spaces to position the line because spacing can change with font or page settings.

The line appears on only some pages: Look for section breaks and check whether Different First Page or Different Odd & Even Pages is selected. Navigate to a page where the rule is missing, edit that page’s header variant, and apply the border there. In a multi-section document, the header may also be linked or unlinked from the previous section; check the Link to Previous setting before changing it, since switching it can affect whether headers share formatting.

You added the wrong border and want to remove it: Click in the affected paragraph, open Home > Paragraph > Borders, and choose No Border. This removes the paragraph’s borders, so if you had other edges you wanted to keep, reopen Borders and Shading and turn off only the bottom edge in the preview instead.

Frequently Asked Questions

Does a bottom border go under the words only?
Usually not. A paragraph bottom border runs across the paragraph’s available width, including its indentation. To make a shorter rule, use a line shape or adjust the width of a text box or paragraph area.

Will the line repeat on every page?
It repeats wherever that same header is used. First-page, odd-and-even, and section-specific headers can be different, so add the border to each header variant that needs it and check representative pages.

Can I add a line under a heading in the document body?
Yes. Click in the heading paragraph in the main document, then choose Home > Paragraph > Borders > Bottom Border. You do not need to open the page header unless the line belongs at the top of each page.

How do I change the line color or thickness?
Open the Borders menu and choose Borders and Shading. Select the preferred style, color, and width, then use the preview to apply the bottom edge only. The available settings can look slightly different across Word versions.

Can I use a keyboard shortcut to add the line?
Word does not provide one universal default shortcut specifically for applying a bottom paragraph border. Use the ribbon menu so you can confirm the correct border. Typing hyphens and relying on AutoFormat is less predictable, particularly in a header.

What is the difference between a border and a line shape?
A border belongs to a paragraph and adjusts with it; a shape is a separate drawing object that you can position and resize. Choose a border for a simple separator and a shape when you need exact length or placement.

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