Many search results promise a "full version free download." These usually involve:

Log in with the linked to your original Office 2013 purchase.

If you just need a Word-compatible program:

Microsoft stopped patching this software after its extended support window closed. Hackers actively look for unpatched exploits in older versions of Office. Opening a corrupted .docx file or an unverified email attachment in Word 2013 could allow malicious scripts to compromise your operating system. 2. Modern OS Incompatibility