The need to drive to a movie rental store has gradually faded as technology has created new options. For instance, iTunes users have the ability to rent movies right on their computer. If you have a mobile Apple product as well, such as an iPhone, iTunes also allows you to transfer the rental purchase to that device. This comes in handy when you want to stockpile rented movies on the iPhone for plane flights or road trips.
Connect your iPhone to your computer using the iPhone's USB connector cable.
Click your iPhone's name below "Devices" on the left.
Click "Videos" near the top of iTunes. A list of your computer's videos will appear, including rented movies.
Click the rented movie, then click "Move." Repeat this step for each rented movie you wish to watch on your iPhone.
Click "Apply" at the bottom right. The rented movies transfer to your iPhone.
Apple gives you 30 days to watch the rented movie before it automatically deletes. After starting the movie, you have 24 hours to finish it before it deletes.