How do I create a a simple correspondence like a 1 page contract or letter, using contact info from YAML? (like a small 'mail-merge' template?)

What I’m trying to do

Emulate an old-school CRM like Goldmine, Act!, Maximizer, EssentialPIM, etc. Contacts have fields, can be very basic like name, address, phone1, phone2, notes area to keep track of conversations, etc. Once a contact has interest in working together, I want to generate a 1 page contract with their info (stored in YAML presumably) autopopulated into the letter/contract template. Like any normal business letterhead (maybe with a graphic logo) and some basics.

Things I have tried

Nothing, I don’t know who to do it – I have a handful of notes (contacts) with names, addresses in properties (fields in CRM parlance)

Not much to be found on this exact topic. Something so simple in CRM, and something that would appear eminently possible in obsidian, as it’s text based, and my task is text based.