Hey Beck,
FFS is an acronym for Facial Feminization Surgery. It is a series of procedures to change the bone structure and tissues of the face to make it appear more like a genetic female. Some people need all of them. Some people only need a few of them and there is a very lucky bunch that does not need it at all.
These include shaving the bone of the browline so it is more flat, like a female, shaving the jaw to make it less square and to make a pointy chin, narrowing the nose, cheekbone inplants, etc. etc.. There are lots of websites of plastic surgeons that show the before and after of these procedures and others advertisements that make everyone think they need all of them. Most of the TS I see, I would not say they need it. However, each person has their own idea of how they want to present, so in the end it's a very personal decision.
Love always,
Elizabeth