Google Docs doesn’t have the Print Merge or a Mail Merge option available, so if you want to create multiple documents from the data you have in your spreadsheet you have to use an Add-on. Usualy these add-ons have limited options and are missing some of the needed functions.
I have been using this Google spreadsheet script to do a Print merge for a while and I have made small adjustments so it can be used by everybody.
With this Google Spreadsheet for Print merge or Mail merge for Google docs you can:
Specify a folder where you want the files to be created
Print merge to a PDF or Google Doc
Send emails with the merged documents
Specify the column with the email address
Add a custom email Subject and Text
If you select Google doc for the Mail merge, the attachment is converted and sent in Microsoft Word document format
Check out the full article here: https://howtogapps.com/print-merge-or-mail-merge-for-google-docs/