Please help with this crazy situation

Tara • 30 year old from the island of Puerto Rico. I`ve been married for 12 years now with my handsome salvadorian husband, Joc.

My best friend is pregnant. Baby daddy is in a relationship with another woman. My friend doesn’t want the baby and now it occurred to her that she wants to put baby daddy’s girlfriend ‘s name in the birth certificate instead of her name, so they don’t have to go through the “adoption “ process. Is that illegal? And how do I explain that to her?