What happened to my Aol mail icon on my iPhone? How will I access mail?

If the AOL app isn't on the home screen, check the App Library (swipe left past your last home screen). If needed, you can use search at the top of the App Library screen. From the App Library you can touch and hold an app and slide it left back to the home screen.

If you don't find it, you can reinstall if from the App Store.

Another option is to use the Apple Mail app to access your AOL mail. See the "Use AOL mail on an iOS device" section of https://help.aol.com/articles/aol-mail-mobile-mail