What's the proper way to package dough? Say I wanted to make a large amount of dough, then divide it into smaller portions to send to cafes, etc. How would I package the divided dough? Do I just put it in a plastic bag or something similar?

Note sure if this matters: the dough will come from an overnight cold rise. Refrigerated shipping will be required.
I would wrap in freezer-safe cling wrap and then put that into freezer-safe ziplock bags. Use sharpie on the outer bags before bagging to write the date and what's in it (or put a sticker on it if this is more of a professional operation or if it's something the public will be buying directly). If this is something you'll be doing a lot you should get a vacuum sealer for the outer bag.