Camera lens got cracked
How much it cost to repair it?
iPhone 12 Pro Max
If apple repairs it, then it will be the discounted cost of replacing the phone according to the schedule in this article
iPhone Service & Repair - Apple Support
Or
Contact - Official Apple Support
Anything other than Screen or Battery may be a replacement phone and the price is in the article under "Other damage"
See also: Get your iPhone, iPad, or iPod touch ready for service - Apple Support