BELOW WE MAY GET STEP-BY-STEP SCREENSHOTS,

Step 1 - Click on "Start" button.

Step 2 - Click on "Settings" button.

Step 3 - Click on "Update & security" button.

Step 4 - Click on "Activation" button.

Step 5 - Verify "Windows is not activated".

Step 6 - Click on "Change product key".

Step 7 - Type valid product key "XXXXX-XXXXX-XXXXX-XXXXX-94VY4" and click on “Next”.

Step 8 - Click on "Activate" button.

Step 9 - Click on "Close" button.

Step 10 - Verify "Windows is activated".

Step 11 - Again, verify "Windows is activated".