Apple care

Screen damage if determined by Apple to be accidental is not covered by the regular warranty. If you have Applecare Plus you get two accidental damages/incidents for the life of the warranty at reduced cost. My understanding is the back glass is fused to the case and cannot be replaced separately. The entire phone has to be replaced.

For the 'iPhone Service Answer Center' click here --> https://support.apple.com/iPhone/repair/service

- includes pricing (note, third party Apple Approved Service Providers may set their own prices).).

Network problems and betrry problems

If the back is not cracked, they can just replace the front screen, however, if its cracked then they will replace the entire thing, You don't get to make the choice.