In Windows 10 , go to Settings >> Update & security >> Activation and click on the Change product key option. Now enter the genuine license and verify it. Make sure that you have an active Internet connection. That’s it.
What happens if I use pirated Windows 10?
Since pirated copies do not receive updates, malware or viruses are more likely to infect them. And a single strain of malware, like the dreaded ransomware, can erase or lock you out of your files. Besides random attacks, the person you downloaded Windows from could have loaded the pirated copy with malware.
Can I update pirated Windows?
Most likely, you have a very old version of Windows 10 installed on your PC, you may need to re-install Windows 10 to upgrade Windows 10 if your version is really old, it will not be possible to update directly. You also need to activate Windows 10 to get full functionality and to be legal.