When a female gets a sex change, where do they get enough skin to make the penis?

Tummy, wrist, etc. There are a variety of possible donor sites but the two most common are the abdomen which can be supplemented with the use of a tissue expander. However another popular option is the use of forearm skin which is transplanted to the genital area using micro vascular techniques.
Transgender. The way they build the penis is done several ways the one my partner does is forearm tissue expander for 6-8 weeks you will be expanded then he will harvest that skin along with urology you will then have the result you need.