Forum Discussion
Why do page number options all have lines?
Why? Because someone at Microsoft likes "fancy" page numbers.
Probably some corporate customer years ago asked for them. They do not all have lines, but generally have something a bit more than a simple page number. These choices make it easy to insert with the fancy formatting, that you (and most of us, I suspect) never need.
You do not need to use these and I seldom do. Using one of them will delete any existing header or footer unless you use the "current position" ones.
Page numbers in Word are fields in a header or footer. You can insert one with the keyboard shortcut Shift+Alt+F9 in Windows. There are numerous other ways to insert them.
For more, see Page Numbers in Word 2007-2021 (365).
Here is a Quick Reference Card on Headers/Footers and Page Numbers in Ribbon Versions of Word.