If you can’t select the line, click in the paragraph immediately above it. In Word for Windows, open Home → Borders and choose No Border. A line that shows selection handles when clicked is probably a drawn object: select it and press Delete.
01Clear the border without deleting the text
Section linkA full-width line that appeared after you typed hyphens and pressed Enter is often formatting on the paragraph above it. Place the cursor there and choose No Border from the arrow beside the Borders button. If other borders disappear too, undo the change and use Borders and Shading to remove only the unwanted edge in the preview.
02Check what actually gets selected
Section linkA line with handles can be deleted as an object. If the line is made of hyphens you can highlight as text, delete the characters instead. If the line sits on the edge of a table cell, work on that cell’s border rather than removing paragraph formatting from text nearby.
03Keep Word from adding the border again
Section linkIn Word for Windows, go to File → Options → Proofing → AutoCorrect Options → AutoFormat As You Type. Clear Border Lines and confirm with OK. This affects future typing; use No Border on the paragraph for any line already in the document.