If you specifically require the 2013 desktop interface (which is now quite old), the closest legal modern equivalent is purchasing a Microsoft 365 subscription. This ensures you have the most secure and stable version of the software.
While the nostalgia for a single-link download is strong, the "portable" dream has actually been replaced by official, safer web versions. Instead of risking an unofficial link, you can access Office on the Web microsoft office 2013 portable link
Microsoft does not offer an official "portable" version of Office 2013. While third-party "portable" versions often circulate online, they are generally unauthorized, potentially unstable, and may carry security risks. If you specifically require the 2013 desktop interface