Provide file downloads to users based on what they bought

[extra-alext]

Hi there, I was wondering if anyone has set something like this up.

I basically need to provide the customer with a PDF file, which is specific to the lot number of the product they purchased. These documents are certificates of analysis for the products.

I don't know if shopify even supports something like per-product unique identifiers or lot numbers.

Does anyone know of some shopify app that can do this? or will I have to make my own?.

Any ideas at all would be appreciated, thanks!

(also not sure if this is the right board, apologies)