A desktop publishing application from Microsoft that focuses on page layout and graphic design.
"Click-to-run" is virtualization technology, different from older install technologies used by Microsoft apps. Click-to-run also lets certain updates be pushed from Microsoft's servers without users running setup.exe (some bug fixes are installed that way).
Older perpetual (one-time purchase) licenses that include Publisher will continue to work even after October 2026. The installation technology shouldn't make a difference.