Kinda. It's different for different people. Many trans women take hormones hoping they'll help them look like a typical gender-conforming cisgender woman.
One other really common reason is that they are deeply upset by and experience dysphoria due to the effects of masculine puberty, and use hormones and surgery to match their body to how they feel it should be. It helps them feel comfortable in their own skin.
I saw a comic from a trans woman once who had recently started hormones, who noticed she had a miserable mood for a few days every couple of weeks for no apparent reason. She marked them on her calendar and found that it was always the couple of days before her HRT shots. She switched from shots every 14 days to every 10 days, and that fixed it up. So it seems that for trans people, HRT isn't just cosmetic, but has a direct effect on mental well-being that's independent of any noticed physical changes.
