@Mark-Hollis, do you want to run your command with multiple parameters? Like this?
notepad one two
If so, do you want to provide those two parameters with your voice? If so, yes, you can provide them via an Alexa routine, but you'll want to use the TRIGGERcmd or TRIGGER command skill instead of the TRIGGERcmd Smart Home skill, and follow this procedure instead:
Open the Alexa app on your phone:
Tap More in the lower right
Tap Routines
Tap the + in the upper right
Tap "Enter routine name" and give it a name
Tap "When this happens" then "Voice" and enter the phrase you want to say, then tap Next
Tap "Add action" then "Custom" then type: "Ask TRIGGERcmd to run notepad with parameter one two"