For the mailmerge basics, see:
How to use the Mail Merge feature in Word to create and to print form letters that use the data from an Excel worksheet - Microsoft Support
Use mail merge for bulk email, letters, labels, and envelopes - Microsoft Support
To split the output into separate documents, see also Send Mailmerge Output to Individual Files and Run a Mailmerge from Excel, Sending the Output to Individual Files in the Mailmerge Tips & Tricks 'Sticky' thread (https://www.msofficeforums.com/mail-...ps-tricks.html) at the top of the Mailmerge forum.

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