HOW DO I ROTATING ART BOARD ?

Hi there, 

Thanks for reaching out. This feature is not available in Illustrator on the iPad yet, however, we're working on it. I'd request that if you could take out a moment and post this as a feature request here: https://illustrator.uservoice.com/. This way you will keep getting all the updates related to this feature & other users can also upvote, which would help us prioritize. 

Regards, 

Srishti