How to print PDF along with some text metadata of it on the same page?

I would like to print PDFs (Invoices received) along with the additional metadata corresponding to those PDFs(my purchase records) on a single page. I have tried MailMerge initially, but at maximum, it can only merge Images on a page. The ideal solution to this problem shall end up taking up metadata (from DB), PDFs (from Drive or Cloud or DB) and put them in their corresponding placeholders in a single page, and output a PDF/Print. Needless to say, the PDFs need to be reduced by approximately 75% to make space for the metadata on the same page. PS: I need to do this for at least 350 invoices.

Question by Keshav on Super User, licensed CC BY-SA. We show a short excerpt and link to the original thread as credit.