Auto-enhance will automatically adjust the exposure and the color, and do what it thinks to make your photo a little bit better.
This feature analyzes the photo and automatically applies changes, like improving the color balance, to enhance the image. Just tap the Auto Enhance icon, which looks like a magic wand and is in the top right corner. The changes can sometimes be subtle, but you'll know they've been made when the magic wand icon is lit up blue. https://www.lifewire.com/edit-photos-iphone-app-2000115