Workflow has built in support for Drafts 4 - but no actions for Drafts 5. This workflow is intended to replace some of that functionality. You can share text to it, get text from the clipboard, type text in, or modify the text on the keyboard to start.
The next step is choosing your action, you can create a new draft, and append or prepend to an existing draft - with the ID of the draft (Drafts Action to get ID).
Next you can choose to run an action after putting the text in Drafts, this is done by typing in the action name, though you may want to replace the
Ask for Input action with a
Choose from List if you have a few actions you regularly use.
You can get the workflow here: Drafts 5