Open the Shortcuts app
Tap the plus icon
Tap Add Action
Search for and select an action
Customize the action if needed
Tap the arrow or shortcut name at the top
Tap Rename to give it a name
Tap Done
To add it to the Home Screen, open the shortcut
Tap the share icon
Tap Add to Home Screen
Tap Add
To use it from Siri, say the shortcut name
To run it from the widget, add the Shortcuts widget to your Home Screen
To run it from the Share Sheet, enable Show in Share Sheet in shortcut settings