Open the Settings app
Tap Wallpaper
Tap Add New Wallpaper or Choose a New Wallpaper
Select a wallpaper from Photos, People, Photo Shuffle, Emoji, Weather, Astronomy, or color options
Adjust the image if needed
Tap Add
Choose Set as Wallpaper Pair, Customize Home Screen, or Set as Lock Screen
Tap Set as Lock Screen if prompted
Press the side button to view the new lock screen
To change the lock screen style, touch and hold the lock screen
Swipe to choose a different lock screen
Tap Customize to edit the current lock screen
Tap Done to save changes