Depending on your license type, the official download process varies:

: Many educational institutions provide free Office 365 Education accounts, which may include the right to download desktop versions of Office apps like Word, Excel, and PowerPoint at no cost. Key Features of Office 2021 Professional

While there is no "free" version of Microsoft Office 2021 Professional for regular users, there are legitimate ways to download the software for installation, provided you have a valid license key or fall under specific educational or professional categories. Methods for Downloading Microsoft Office 2021

: If you bought a retail version, you can redeem your product key at the Microsoft Office Setup page. Once verified, the installer becomes available in your Microsoft account under "Services & Subscriptions".