Do i Need an External database for my goals?

Hi all, i am new here with ejabberd and i need some advice to achieve my goals developing with xmpp. I posted here because one of my main doubts it's about the usage of an external database.

For example, i don't know what data per user is stored in the ejabberd embedded database, and i need to send some information from user to user, for example, the location of the user, then, for example the user birthday, and a personal message given by the user, so, as i understand xmpp is no more just that xml format messages, called stanzas, they are in various flavors, like message, iq, etc. The question is, do i need an external database with the information i'm interest to transmit, get it via iq stanzas? what fields and tables does my external database should have to make authentication and a correct working flow with messages and MUC's should it have?

I am working with xmpp framework in iOS. Hope you can give me a correct guidance.