PFOA was the surfactant that was used to keep Teflon in an emulsion during coating processes. It was replaced in the 2000s with an alternate product branded GenX that was supposed to be safer, but in actuality ended up being more toxic than PFOA.
In either case, the main exposure risk is to those surfactant chemicals, typically due to groundwater contamination near a plant or via occupational exposure. Once in a finished coating, Teflon itself is essentially inert unless you heat it up several hundred degrees, so existing nonstick pans and other finished products don’t pose too much risk.