Logic Remote for GarageBand User Guide
Remote control your music
Logic Remote lets you control Logic Pro and GarageBand on the Mac using your iPad or iPhone, and it lets you control MainStage using your iPad. You can record, mix, and even play Touch Instruments from anywhere in the room using Multi-touch, turning your iPad or iPhone into a mixer, a transport control, and a flexible Touch Instrument.
To learn more, see Get started with Logic Remote