Please am new to this platform,have been reading and taking notes,but i need more clarifications and advices.

I intend to apply for a medical visa to have my baby is California, but haven't gotten an invite, can i apply without an invitation letter? Also my DH has a British passport,shld I mention this at the interview,and he's sponsoring the trip,how much should be in his account to satisfy the VO.

Pls need your honey advice