I know mine only cause they've talked to my friends and family

Most of our alters came to us with names. There's a handful that didn't, so we picked nicknames until they decide

My alters have names I don’t know if I named them or they named themselves, the names just always seem to be there.

Mine all have the same name just different personalities and I can't remember a lot because my mind is so fragmented.

We just kinda started naming people whatever the host thought was fitting and if anyone didn't like their host given name they were free to pick a different one. Although eventually when people showed up they just gave themselves a name, or already had one from source memories

My System uses an app called Simply Plural. It's a System (or friends of systems) app to keep track of alters and not only their names but their ages, their roles in the system, their likes and dislikes, information they may want to be known. It also gives you the option for a pic of what they look like, (or as close as possible to it) and their preferred pronouns. It also has the ability to keep track of who is fronting (as long as they take the time to change it in the app) and has the ability to notify friends or family that have the app and who have your information of who is fronting at the time so they can also keep track. (Only you can give them that information, they can't access it without you)

We decide our names ourselves or come with them already, at best the rest of the system just gets to veto a name we have a problem with