Submitting Professor Rec through common app

Do I need to give my professor physical stamped envelopes? Or after submitting their emails into the common app thingy, will they be able to just send them electronically somehow? One of my profs I’m choosing has never done transfer recs before, and I want to make the process as easy for her as possible

Bumping. Am interested in this as well.

Really? No one knows?

I believe that once you input your recommender’s email and assign it to your school, he or she will get a link that allows them to upload their letter of rec. Well that’s what it says on commonapp.