All SnapGene files are stand-alone files whose properties can be managed using options available in your operating system.
For Windows see: https://www.google.com/search?q=how+to+make+a+file+read-only+in+windows+10
For macOS see: https://www.google.com/search?q=make+a+file+read-only+in+macos&
If you set a file as read-only then users will be able to open and edit the file, but they will not be able to "Save" and will need to "Save As" to create a new separate edited version of the file.
You can CTRL-click on a file in a Collection and choose to "Reveal in Finder" (macOS) or "Reveal in Explorer" (Windows) to locate a file and change read/write permissions.