Cracked Screen on loaner phone

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.

iPhone Repair - Screen Damage [and links to other iPhone repair services] - https://support.apple.com/iphone/repair/screen-damage - includes pricing.

iPhone Service Answer Center - https://support.apple.com/iphone/repair/service - "Learn more about iPhone service options, warranty, and pricing." Repair times.

Genius Bar appointment - Go to https://www.apple.com/retail/geniusbar/ > Get hardware help > iPhone > Repairs & Physical Damage > Screen is cracked > Bring in for Repair --> Sign in with Apple ID

Do not get it repaired by a third party place. You may wish to contact Apple about the best way to handle this:

Contacting Apple for support and service - http://support.apple.com/HT201232 - select country

I personally would not take a loaner iPhone to a third party for repair. There is a good chance that Apple will charge you for it after doing that.