A woman is an adult female human. (Similarly, a man is an adult male human, and everything that applies to one applies similarly to the other.)
Nothing you can do can change a male human, with XY chromosomes, into a woman. Not surgery, not hormones, not behaviour.
If a person has such self-hatred or confusion that they do not want to be their sex, that is a mental illness on a par with anorexia. The person and the illness should be treated with compassion, with a view to recovery, not with affirmation, not with the expectation that society should collide in the delusions caused by the illness.
If a person does not want to present or perform according to the gender-norms of their sex - then why should they? He can wear a dress, she can be a lumberjack, etc etc. They are no less male or female for doubt by so.
Gender non-conformists may find that society struggles to accept their variance from the norm. The problem usually lies with men being unwilling to accept variance from the norm, and responding aggressively to it.
The mentally ill person may not have found relief with therapy and, as a last resort, may choose to modify their body. Similarly, the non-conformist may choose to do so. Adults may do what they like to their own bodies. It still does not change their sex.