Replacing Iphone 7 battery

The Apple Store or an authorized Apple Service will NOT sell a genuine battery to you.....and you need a genuine Apple battery if you want Battery Health to work properly. So, only get the iPhone serviced at the Apple Store or authorized Apple Service shop.

Cost will be about $50 U.S.

Replacing the battery in anything newer than an iPhone 4 is very difficult, if not impossible, for the average person. Your best bet is to either carry a portable battery pack or upgrade to a new phone. You can take your phone to a shop and see if they will do it, but how much that costs depends on the shop.

Apple will replace it for $49. iPhone Battery Replacement - Official Apple Support