Licenses for intercompany process

Hello.

We are developing an add-on that runs on company A and needs to create documents in a second company B. What licenses are needed in both companies to be able to do this. Will a professional user in both companies be enough or are there special licenses needed for this task?

Maybe someone can provide a link to a source that describes licenses that are relevant for running add-ons or explain the licensing model for add-ons in his/her own words.

Thanks in advance.