OS X Mountain Lion: Create templates
You can make a file into a template, or “stationery.” When you open a stationery file, a copy of the original is opened. You can edit the copy and save it, but the original file remains untouched.
- Select the file you want to use as a template, and choose File > Get Info or press Command (⌘)–I.
- In the General section of the Info window, select “Stationery pad.”
If you ever need to change the original, repeat the steps but deselect Stationery Pad. Then open the file and make your changes.