how do i recover a deleted app on my iPhone

Open the App Store > Look for the app and you should see a cloud icon next to it. Tap the cloud icon and it will redownload to your iPhone. If there is no cloud icon next to the app, it means you just removed the app from your home screen. On your home screen swipe from right to left till you arrive at the App Library. Look for the app there and move it back to any home screen page you want.

Tap to select the App Store and use the search window to type in the name of the app. You can download it again, assuming it is not an old out of date app and you really did delete it.