Everyone in your immediate family would all use the same call sign. You all have to ID with the call sign every 15 minutes of conversation and at the end of the conversation, regardless of the duration.
You can add additional identifiers if you would like. An example would be, everyone in my family would use ABCD123, but I may ID my station as ABCD123-ALPHA. My wife would ID as ABCD123-OMEGA. My son could be ABCD123-BETA.
Again, the add-on ID is optional... but legal. For what it's worth, no one in my family uses add-ons. We all just use ABCD123 and call each other by name.
