how do i delete my apple account

If you mean how can you delete your iCloud account, go to Settings>iCloud, scroll to the bottom and tap Delete account and provide your password if prompted.\

Note: this deletes the account from your device, not from iCloud. You can't delete an account from iCloud, you can only choose to stop using it.

If i delete my icloud account from where you wrote. Does it delete the apps i have on the device as well (ipad mini)? Or just the account and contacts, photos etc?

Message was edited by: cknorthpole

The apps are tied to the iTunes login: this doesn't have to be the same as the iCloud login, though it often is, and isn't related to iCloud either way; so disconnecting your device(s) from iCloud will have no effect on apps or other items purchased through iTunes.