Or you can right-click on Windows logo > System > under “Related settings” click System info. If you want check your Windows 10 activation status, use Windows 10 keyboard shortcut by pressing Windows logo + I > Update & Security > Activation.
If you don't activate your Windows 10 installation, you break the Microsoft EULA. Some generic keys have 90 days trial period before you must activate it permanently. Retail generic key doesn't have an expiration date, and it won't activate the Windows either. This generic key usually used for testing purposes of installing Windows 10 on a PC or virtual machine before decided to buy a genuine key. To activate your Windows 10 installation, you need a Windows 10 genuine key. You can install Windows 10 using generic keys, but it will NOT ACTIVATE it. You can buy from Microsoft store directly or from their certificate stores, or you can use a generic product key for free. There two options to get a Windows 10 product key. However, the steps to retrieve product keys for older Windows versions may differ.When you install a specific edition of Windows 10, you need a product key for Windows 10. In addition, to deinstall or reinstall another Windows version you might need a Windows 7 product key or Windows 8 product key.