how to transition to formula

i’m looking for advice on how to transition my baby to formula. she’ll be 1 month next week and unfortunately i can’t breast feed her anymore because i’m going to be going through cancer treatment when she’s about 2 months. i want to start weaning her at 1 month so the transition can be as smooth as possible. she takes breast milk perfectly fine from a bottle and i end up giving her more feedings from a bottle than from the breast anyways. do you mommas have any advice on how to start this transition and what formula i should use? thank you in advance!