Activation helps verify that your copy of Windows is genuine and hasn’t been used on more devices than the Microsoft Software License Terms allow.
	
Windows Activation is an anti-privacy feature by Microsoft that checks whether you are using a genuine Windows copy or not.

License for software:
Retail - from retail store partners or from online stores
Volume - from organizations such as school, gov't., business
OEM- from manufacturers for new devices.

Digital license - method of activation in Windows 10 that doesn't require you to enter a product key.

Online activation- is a method to activate your OS using internet connection to register your license from MS server.

Phone activation - method used to activate your OS by calling the designate phone number for your region. It will provide you a long set of number (Installation ID) and you need to generate a confirmation ID using your PACSR tool.

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