Formula???

BabyBlu🐼 • Mom of Irish twins
Hi ladies! I need to start supplementing maybe switch over to full formula here in a few months. Can you please tell me in your opinion, which formula is best for supplementing or best formula in general and why? My baby girl isnt very fussy and she did get a bit of premade bottle formula as a newborn in the hospital and for about a month after but we have been breastfeeding ever since. Im trying to compare on contrast but i would like to know where to start.