Q: How can I delete a movie when it starts downloading?p

Greetings Abduljaroudi,

Welcome to the Apple Support Communities!

I understand that you are looking for information on deleting content that has downloaded to your iTunes library. To complete this task, please read over and use the information provided in the attached article. 

How to delete content you've downloaded from the iTunes Store, App Store, iBooks Store, or Mac App Store - Apple Support

Cheers,

Joe