Everton will pay no transfer fee, but FIFA training compensation will be applicable.
Mustafi is a centre-half of Albanian descent and is expected to link up with Andy Holden's reserve squad once pre-season is completed.
Everton chief executive Robert Elstone, meanwhile, has confirmed that the Goodison club is negotiating for an extension of Manchester City striker Jo’s loan, as reported in yesterday’s Daily Post.
He said: “We've had a conversation with City over the options available and discussions will continue.”
