What type of "project" ??
What software are you using?
You sure you don't mean a pdn file?
Generally, you'll want to do a "Save As"
AND then choose from the drop down menu, which format / file extension you want to use.
In most software, a "project" is just that.... a project and as such, is not a completed or finished product
AND
Most "projects" can only be opened with the software they were created with