I'd like to have the document path inserted by default on every map (that I can then delete if it's not needed) because I keep losing track of the electronic versions of maps for older ones (ca. 2012) I have printed, and my brain seems far too taxed to remember to add it each time. I have the standard ArcMap license with 10.3.
You can create and save different map templates based on your preferences. Check out the Using Map Templates help page.
Just add the dynamic text the the mxd, and follow the steps to save it as a template, then use this as your default to always have the path set automatically.