Apple TV +

If you redeem the free offer within 90 days of activating the phone and it was purchased from Apple or an authorized Reseller

Apple TV + Offer

https://support.apple.com/en-us/HT210573

Yes, to avoid any charges cancel at least 24 hrs before the trial period ends. You can set a reminder so you don’t forget.

Please note if you cancel while the free subscription is still active, you cannot change your mind and reactivate the free trial

Yes.

Note: When you cancel the subscription, the service will terminate immediately,