I'm not aware of any "template" feature in Notepad on the OmniGo.
The first work around that comes to my mind is to make duplicates of the entire "template" document using Copy and Paste at the screen which displays the documents by name, retaining one "virgin" copy prior to editing. If the first characters in each file are the patient name or some other identifying information, then you'd be able to distinguish the files by the display on the right side of the document list. Or you could rename the documents themselves. Using the "category" feature would allow you to have different templates for, say, different diseases, and limit the display to only one category at a time.
Steve