Not sure if this is what you mean, but this is what I do. If I'm making a post for an affiliate, I put a link to their appropriate page into my post. Personally, I like boosting the post, because then there are more stats available (insights) that show click through, etc.
For example, on this Facebook post https://www.facebook.com/justlikeoma/photos/a.10150268831596780.325130.245157921779/10153777683016780/?type=3&theater
I used a link shortener so that the url won't be too long within the post. Payment was arranged before I posted. However, it's also possible to choose to be paid per click. It depends on what you arrange with the brand.
You'll need to make sure you specify that the post is an ad ... hashtagging it with #sponsored or #ad or #affiliate ...
You'll also need to check with whomever you are affiliated with if they have restrictions on social posting, if you're doing this on your own. However, if you're working personally with a brand, you can arrange how the money flows and what they want.
Just recently, Facebook starting providing an icon at the bottom of the post where one needs to tag the brand ... I haven't had the opportunity to use that yet. Check here: https://www.facebook.com/business/news/branded-content-update
for more info. At present, it only works with verified pages ...
Is this what you are referring to?
PS: BTW, there are no daft questions