Breastfed baby to bottles

Amber

I’m going back to work in a month and need advice what to do for my baby. He takes bottles occasionally but mostly just feeds off of me. But since I’m going back I want to start using bottles to get him ready to transition. Is this necessary? Also, he started this thing where he bites down on the bottle and releases and spits milk everywhere. Is there a way to make him stop doing that?