Any candidate for phalloplasty needs 2 letters from mental health professionals and 1 letter from their personal doctor. One of the mental health referrals needs to come from someone at the doctorate level (so PhD, PsyD, etc.).
Letters from mental health practitioners should address: who they are, how they are qualified to assess transgender or intersex patients for surgical referrals, that you are the age of majority in your country, that you have an official diagnosis (with provided evidence), that you have no additional mental health concerns or if you do that they are well managed, and that you are educated on the procedure you are seeking.
Letter from doctor should address: how long you have been receiving HRT, that you have the capacity to make an informed decision and consent to treatment, that you are the age of majority in your country, that your medical or mental health concerns are well managed, and their agreement that surgery is both medically necessary and appropriate for you.
So I would start by meeting with your doctor and telling them this is the procedure you want and that you need a letter containing all of the above things. I would ask them to refer you to a therapist who can evaluate your case and write a letter containing the above things. I would ask that therapist if they know a psychiatrist who can evaluate your case and cosign their letter.
While you're in the process of getting all that together, you can schedule a consult with the surgeon of your choice. Some of them will not agree to meet with you unless you have letters already.
I would check with Tricare and see who they are currently covering for phalloplasty. I can't think of any surgeons off the top of my head that do. But there's no use getting your heart set on a particular surgeon only to find out insurance won't cover them.
