Do I need a work permit? How should i go about this?

An iphone app wants to hire me to make videos for them each month for a few months. I'm only 15, so I'm not sure if I need to get a work permit or if I even can work for them.

Yes, you need a work permit. You can work for them, but there's a maximum number of hours you can work each week. The times during which you can work are also limited. Child labor is regulated by both state and federal laws, so the rules will depend on the state in which you live.