Question: how to change your background on a phone?
Answer: Open Settings on your iPhone. Go to Settings, tap Wallpaper, then tap Choose a New Wallpaper. ... 
Choose an image. Choose an image from Dynamic, Stills, Live, or one of your photos. ... 
Move the image and choose a display option. Drag to move the image. ... 
Set the wallpaper and choose where you want it to show up.