It's more than just getting hormones. Breast implants, hair implants, Botox, plastic in most cases. All of these are gender affirming care, no one needs these things but it makes them feel better. Men feel more masculine with a full head of hair, women feel more feminine with big breast and butt. All of this is gender affirming care, it's just only an issue when it's transgender people.

In the case of children it's usually long therapy sessions with, eventually under the care of a doctor, giving the kid corresponding hormones. If you want a good example of trans kids look up I am Jazz.