Buying

[Szófia]

i do not know how to switch on ask to buy on icloud settings.

[jeffkinn]

You're going to have to explain more fully what you want to do. Ask to buy what?

If you mean get extra storage in iCloud go to 

settings - storage & icloud usage - icloud manage storage - change storage plan

[BandOfBrothers]

Yes please could you elaborate.

 How to buy Apps and content is explained in > Payment methods that you can use in the iTunes Store, App Store, and iBooks Store.