There is enormous confusion about this. I'm not surprised that laypeople and non-scientists are ignorant of what bodily changes trans people have, but it's terrifying to think that the HCPs of the future are having nonsense like this taught to them at university level.
As far as I understand it, and I am definitely a layperson and non-scientist, this is the current position.
Anybody can call themselves trans, whether or not they are planning to have/have already had any medical treatment. There is no gatekeeping of any kind unless you want a gender recognition certificate.
Transwomen are male. They may have any of the following, or none.
(a) Electrolysis to get rid of facial and body hair.
(b) Facial feminisation surgery, i.e. cosmetic surgery to change the bone structure of the face.
(c) Shaving of Adam's Apple to make it less visible.
(d) Hormone treatment to suppress testosterone levels and massively boost levels of oestrogen and sometimes progesterone - this will reduce facial hair, increase breast tissue and reduce penis size, but won't grow a female reproductive system, nor will they start having a menstrual cycle. Results in mood changes.
(e) Sexual reassignment surgery - rare (fortunately, as it's major surgery, high risk of post-op infection, and gives poor results). This involves removing the testicles and operating on the penis to make it something like a clitoris. An artificial opening is created in the scrotum using colon tissue. This is called the neovagina and has to be kept open by dilating it daily, as otherwise the body would heal it up. It won't result in the transwoman having a womb or ovaries or being able to become pregnant or having a menstrual cycle.
Transmen are female. They may have any of the following, or none.
(a) Double mastectomy, euphemistically referred to as top surgery.
(b) Hormone treatment, i.e. medication to stop the body producing the normal amounts of progesterone and oestrogen, and to massively boost the amount of testosterone. Results in permanent deepening of the voice, growth of facial hair, mood changes. May lead to vaginal atrophy, urinary problems and increased risk of cancer and heart disease.
(c) Hysterectomy, possibly also with removal of the ovaries. Obviously results in loss of fertility and onset of menopause, which increases risk of heart disease and osteoporosis.
(d) Sexual reassignment surgery, euphemistically known as 'bottom surgery'. Very rare, fortunately, as this is major surgery and results are extremely poor. Involves taking tissue from another part of the body, typically the lower arm, which is left permanently disfigured, and making a crude facsimile of a penis out of it, incorporating the clitoris. It won't ejaculate. Ability to orgasm is likely to be lost.
There are many differences between the sexes which can't be changed. Height, shoulder breadth, hip width, gait, size of hands and feet relative to the rest of the body - all of these are clues to the sex of an adult which we register automatically, just like all other animals with two sexes. Also, the size and composition of muscles is different in each sex, and males have larger hearts and lungs in proportion to the rest of the body, so taken with their greater height they are always going to be stronger than females, even when testosterone levels are reduced.
If I've got this mostly right, maybe I could get a job producing the next workbook. Sounds like I couldn't do any worse.