Double click on the header to starting editing.However, using this way, you will also remove other formatting in the header or footer, such us text centering. In this section, we will first present you with a simple way to remove these horizontal lines. Method 1: Remove the Line Together with other Formattings To remove these unwanted lines quickly, you can refer to the following instructions. However, Word does not allow you to highlight or select it, and therefore you cannot easily get rid of them. Sometimes, you may find an unwanted horizontal line after you insert header or footer to your Word, just like this: This article will show you how to get rid of it. When you insert header or footer to your document, Word voluntarily adds a black horizontal line to the header or footer.