My preferred approach would be to employ a separate Word document as a mailmerge main document, then merge the Excel records from there.

Using a mailmerge allows you to generate multiple certificates at the same time. If you want to produce only one or a few certificates, you can use the mailmerge filters for that. And, if you want the output to go to separate files, see Send Mailmerge Output to Individual Files in the Mailmerge Tips and Tricks 'Sticky' thread at the top of the mailmerge forum:
https://www.msofficeforums.com/mail-...ps-tricks.html

For the mailmerge basics, see: Mail merge using an Excel spreadsheet - Office Support

__________________
Cheers,
Paul Edstein
[Fmr MS MVP - Word]