If you have a computer at home with Office 2013 installed, leave it on.
While "portable" versions found online are unofficial and often carry security risks, you can still download the official installer if you have a valid product key. Official Installer : You can download the installation package from the Microsoft website Service Pack 1 (SP1) microsoft office 2013 portable link
Office 2013 (unlike Office 2010) used Microsoft's App-V (Application Virtualization). It creates a virtual file system and registry. To run it from a USB drive, you would need to carry that virtual environment with you—which is roughly 2GB of data. But that virtual environment links to hardware IDs. Move the USB to another computer, and the virtual environment rejects the new hardware. If you have a computer at home with
For true portability on the go, use the official mobile apps: Tablets/Phones It creates a virtual file system and registry
There is no scenario where downloading a "portable" repack of Office 2013 from a random forum ends well. At best, you waste 2 hours downloading a corrupted RAR file that crashes when you try to save a document. At worst, you hand over your bank account credentials to a hacker in Eastern Europe.
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