Taking Apple 1 1 and iOS 14.2 systems as examples, the ways to set the appropriate size of Apple mobile phone wallpaper are as follows:

1. Open the "Settings" option of the mobile phone, find "Wallpapers and Brightness", and click Enter.

2. Click "Select Wallpaper". In the wallpaper selection option, you can choose Apple's wallpaper, or you can choose the pictures in the mobile phone photo album.

3. Select the wallpaper, and then the "Settings" button will pop up at the bottom. Click the Settings button.

At this time, you can use two fingers to slide on the screen of the mobile phone to change the size of the mobile phone wallpaper.

5. There are three options in the wallpaper settings, namely setting the lock screen, setting the home screen, setting at the same time, and clicking Settings.

Set to lock screen, set to home screen and set to at the same time. These three options are very simple, because lock screen wallpaper and desktop wallpaper can be the same or different, so if you need to set this wallpaper as lock screen or desktop wallpaper, just choose to set it as lock screen or set it as home screen directly. If you set this wallpaper as lock screen and desktop wallpaper at the same time, choose to set it at the same time.

This answer applies to most of Apple's mobile phone models.