Potty training involves teaching a child to be independent with their toileting skills. Clearly an infant cannot dress or undress themselves, or even walk themselves to the bathroom!
However, there’s a practice known as Elimination Communication which can be implemented from as young as birth. It involves you observing your infant’s cues and holding them over a sink, toilet, or other vessel when they need to pee/poop. EC is adopted from methods used in East Asia and has become increasingly popular, but it’s not officially considered potty training.