Open the Settings app
Tap Wallpaper
Tap Add New Wallpaper
Choose a wallpaper from Photos, People, Photo Shuffle, or Weather
Adjust the image position and size if needed
Tap Add
Select Set as Wallpaper Pair, Set as Home Screen, or Set as Lock Screen
Tap Done
Or open the Photos app
Select a photo
Tap the Share button
Tap Use as Wallpaper
Adjust the image if needed
Tap Add
Choose where to set it
Tap Done