Difference between Create New Project and Create New Project template?

[epolydorou01]

What is the difference between Create New Project and Create New Project template?

[HVAC-Novice]

Check out what templates do... and create one that works for YOUR needs. 

https://knowledge.autodesk.com/support/revit/learn-explore/caas/CloudHelp/cloudhelp/2021/ENU/Revit-C...

The one creates a project, the other a template (you probably could see that :-). You can create a project from the template, or a project can be saved as a template.  

[ToanDN]

One creates a new RVT file format and the other creates a new RTE file format.