Microsoft Office 2003 was never free. Any download labeled "gratis" from Softonic, Archive.org, or torrent sites is pirated software . Softonic is also known for bundling adware, browser hijackers, and potentially unwanted programs (PUPs) with third-party downloads.
Microsoft ended support for Office 2003 in 2014 . It has known, unpatched vulnerabilities that can infect your PC with malware, ransomware, or allow remote code execution. Running it on a modern Windows version (10/11) is highly risky even if you find a legitimate installer.
I understand you're asking about a "deep paper" or analysis related to the search phrase (Spanish for "download Microsoft Office 2003 free Softonic").