Custom app icons are only available on macOS.
You can personalize your Craft app by setting a custom icon on your Mac.
Set a Custom Icon
Open the Applications folder on your Mac
Right-click on Craft and select Get Info
Drag and drop the .icns file to the small Craft logo in the top-left corner
The custom icon will reset to default whenever the app updates. This is a behavior imposed by the App Store.
Delete a Custom Icon
To reset your icon back to the default:
Go to the Applications folder on your Mac
Right-click on Craft and select Get Info
Click the app icon in the top-left corner
Press Delete on your keyboard