Most "portable" Office 2013 releases are liars. When you run them, they inject 500+ registry keys into the host machine. They are not "portable"; they are simply "pre-activated installers" that uninstall themselves when you close the USB drive. This often corrupts existing Office installations.
The keyword refers to a specialized, non-standard version of the classic Microsoft Office 2013 suite, repackaged to run without a formal installation. While the idea of a "portable" office suite that fits on a USB drive is appealing, it comes with significant security and legal caveats that every user should understand before downloading. What is a "Portable" Version? microsoft office professional plus 2013 portable 2021