can I add another iphone to my account

Hello DGRPQ0,

I am not clear as to which account you are referring. If you mean to your Apple ID, you can add up to 9 additional devices. Read this link please --> Sign in with your Apple ID - hhttps://support.apple.com/HT204053

I understand that you would like to add another iPhone to your Apple ID. The answer to your question is YES you can.

Axel F.