When I first started transitioning, I opened a new (temporary) Facebook account for my new identity, while keeping the old male one alive. Be really careful if you do that, so that FB doesn't figure out that you are the same person: use different browsers or different devices for the two accounts, and allow NO friends in common between the two. Otherwise FB will out you be suggesting your new name as a 'friend' to your old friends.
When I was ready to come out to the world, I posted a coming out notice on my male FB account. Then, a few hours later, I changed my name and photo on it. There is an option, buried somewhere in Settings, to change your FB username, which I did, so my page no longer has my deadname in the URL.
Finally, I transferred membership in my support group's FB page from my temporary to my regular account, informed my friends there that they could find me on the other account, and then closed down the temporary one.