Modify shortcut colors and icons on iPhone or iPad
By default, new shortcuts display a magic wand icon and one of 15 colors. You can customize the shortcut’s appearance (the rectangle in your shortcuts collection) by changing its color and giving it an icon more representative of its task.
When you add a shortcut to the Home Screen of your iOS or iPadOS device, you can use a photo from your photo library as the icon. See Add a shortcut to the Home Screen on iPhone or iPad.
In My Shortcuts
in the Shortcuts app on your iOS or iPadOS device, tap 
on the shortcut you want to modify.Tap the Icon next to the shortcut name, then do any of the following:
Change the shortcut’s color: Tap Color, then tap a color swatch.
Change the shortcut’s glyph (icon): Tap Glyph, tap a category at the bottom of the screen (Objects, People, and so on), then tap an icon.
For information on the Home Screen options, see Add a shortcut to the Home Screen on iPhone or iPad.
To save your changes, tap Done.