Hi, I'm John! I will help you with this.
To help narrow down the issue:
- Did your PC originally come with Windows 10 Pro, or did you upgrade from another edition (like Home)?
- Do you already have a product key or digital license, or are you looking to purchase one?
- Is there any error code showing when you try to activate?
If you don’t already have a valid product key, the safest way to get one is by purchasing directly from the Microsoft Store or an authorized retailer. Once you have it, you can enter the key under Settings > Update & Security > Activation.
With a few more details, I can guide you step by step on what to do next.
Click "Add comment" to let me know.
Regards,
John J.D.