In order to activate Windows 10, you will need a 25-character product key or a digital license.
Depending on how you got your copy of Windows 10 will determine how you find your product key to activate. Without one of these options you will not be able to activate Windows 10.
A new PC with Windows 10 installed
The product key is preinstalled on your PC, to find the key check the packaging the PC came in, or it can be included on the Certificate of Authenticity (COA) attached to the PC. For more info, contact your hardware manufacturer.
A physical box copy of Windows 10 from an authorized retailer
The product key is on a label or card inside the box that Windows came in. For more info, contact the retailer that sold you Windows 10.
A digital copy of Windows 10 from an authorized retailer
Find your product key in the confirmation email you received after buying Windows 10 or in a digital locker accessible through the retailer’s website.
A digital copy directly from Microsoft
The product key is in the confirmation email you received after buying your digital copy of Windows. Microsoft only keeps a record of product keys if you purchased from the Microsoft online store. You can find out if you purchased from Microsoft in your Microsoft account Order history.
Windows 10 store app
If you bought Windows 10 Home, Professional, or upgrade to Pro in the Windows 10 Store app, you'll receive a digital license. You can use the digital license for activation.
Free upgrade to Windows 10
If you upgraded from Windows 7 or Windows 8.1 for free, you should have a digital license.
Locating your product key for Windows 7 or Windows 8.1
If you purchased a physical box copy of Windows, the product key should be on a label or card inside the box that Windows came in. If Windows came preinstalled on your PC, the product key should be on a sticker on your device. If you’ve lost or can’t find the product key, contact the manufacturer.