A family of Microsoft spreadsheet software with tools for analyzing, charting, and communicating data.
Hello,
As for the headers and footers, they cannot have borders like cells are. It is working as designed. If you wish to have a header with boarders; an alternative is to use the the first row of cells as a pseudo-border by merging them. From there, you can adjust the merged cell's height and edit the font size and alignment. Please take note that this alternative may be tedious, specially if you are working on multiple pages, as you will be performing them manually.
If you feel that there is the need for additional features for better usage of the app, we highly encourage you to have any feedback or suggestions that you have in mind posted to our Excel UserVoice page for our system engineers to know what would users like to have in future update.