Hello @KerenB ,
It's not really possible through our systems to have individualized content to that level.
You could utilize a cloud service to upload all of those documents already typed out with names, etc. Then from there you add each individual certificate's cloud share URL to the corresponding contact as a custom field. In your emails you'd likely want to mention something about how they'd need to copy and paste the provided URL into their browser's address bar, then use Insert Contact Details to have that coded bit of info be present. It's a very roundabout, but technically plausible way of doing it.
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