Go to office.com. Log in with your Microsoft Account and enter your 25-digit product key. This "binds" the license to your account forever.
Ensure you aren't trying to install it on a second computer; Home & Student is strictly for one device . Go to office
: Most free keys are already used or fraudulent , resulting in an "unlicensed product" error immediately or shortly after use. Go to office
If you bought a physical box or digital card from a retailer (like Best Buy or Amazon), locate your 25-character product key. If you do not have one, proceed to Step 2 to install the trial. Go to office