Step 1. You need to have a product key, if you do not have one, just go to https://rossom.store and purchase one for a cheap price.
Now when you have you product key, move to the next step so you can activate your windows 10/11.
Step 2. Press Windows icon on the keyboard > Settings > Update & Security > Activation (or you can input Activation on the search box after setting page pop up.)
Step 3. Click the Change product key.
Step 4. Enter your product key > Click Next > Select Activate
And done, your windows10/11 is activated now.