What hormones are being replaced?
It's not HRT. Hormone replacement therapy is for women undergoing menopause who are no longer producing the hormones their body needs to stay healthy.
Men identifying as women are not experiencing a loss of hormone production. Therefore they are not in need of HRT.
As an FYI, advocating that transwomen need to take hormones, or do anything at all to their male bodies in order to "be women", is regarded as very transphobic in some quarters.