The correct solution would be to edit the mailmerge main document, then re-run the merge. Mailmerges don't output extra pages without there being something to cause that in the mailmerge main document or whatever process you're using to generate the separate files. For a macro to generate individual output files from a mailmerge without the addition of extra pages at the end, see
Send Mailmerge Output to Individual Files in the
Mailmerge Tips and Tricks 'Sticky' thread at the top of this forum:
https://www.msofficeforums.com/mail-...ps-tricks.html