How to buy Windows 11/10 with a valid or legit license key
Buying Windows 10 means buying a License key. Yes, you will get an option to download, but the key can only activate it, and make it a valid copy of Windows. Sometimes the websites might offer you to get a USB drive if they are available to ship in your area. In case you are still not sure which Windows edition to buy? Read: Precautions to take when buying Windows and Office product licenses.
1] If you have already installed Windows 11/10
If you have a Windows 11/10 PC, but without any activation, all you need to do is buy a license. Go to Settings > Update and Security > Activation, and use the link to purchase a license of the correct Windows 10 version. It will open in Microsoft Store, and give you the option to buy. Once you get the license, it will activate the Windows. Later once you sign in with Microsoft account, the key will be linked. You should get an email from Microsoft with its key.
2] Buy from Microsoft
The best place to buy Windows 11/10 is from Microsoft.com. You will have an option to download the ISO or get a USB. In either case, the activation keys will be sent to you over an email. Once you have the keys, use to activate Windows 11/10. While you can stay without activating Windows, since you have the key, its best to use it. Read: Are cheap Windows keys legit? Do they work? Read: How to validate Windows product key? Lastly, if you already have any of these versions, especially Home, and you wish to upgrade to Pro, this Windows version upgrade guide is all you need. Now read: Why not to use a Pirated copy of Windows.