Hello Victor Flores,
When you buy the upgrade from Home to Pro via the Microsoft Store, Microsoft does not send you a product key. Instead, the license is digitally linked to your Microsoft account and the hardware ID of your device. That is why you cannot find a product key in your email or account. Activation should occur automatically once the upgrade is installed, provided you are signed in with the same Microsoft account used for the purchase.
To resolve this, open Settings > System > Activation. If the edition still shows Windows 11 Home, select Change product key and enter the generic Windows 11 Pro key:
VK7JG-NPHTM-C97JM-9MPGT-3V66T
This key does not activate Windows but forces the edition switch from Home to Pro. After the edition change, Windows will attempt activation against your digital license. If your purchase was successful and tied to your Microsoft account, activation will complete automatically.
If activation fails, confirm that you are signed in with the same Microsoft account used for the purchase. You can also check your purchase history at account.microsoft.com > Services & subscriptions. If the license is listed there, but activation still fails, run the activation troubleshooter from Settings > System > Activation > Troubleshoot.
In short, you do not need a product key. The upgrade is digital, and the generic Pro key is only used to switch editions. The actual activation is handled by your Microsoft account license.
I hope you've found something useful here. If it helps you get more insight into the issue, it's appreciated to accept the answer. Should you have more questions, feel free to leave a message. Have a nice day!
Domic Vo.