Ni jiao shen me ming?

In Mandarin, if you want to know the name of a person, you will say, 'Ni jiao shen me ming? (What's your name?)'

The person you have addressed the question to will reply, "Wo jiao John." if his name is John.

As for the pronunciation, jiao sounds like chiau, shen is pronounced as 'tion' in action and me is articulated as ma as in machine.
Happy asking your friend's name with 'Ni jiao shen me ming?'