McAfee will provide you a 25 character alphanumeric key while purchasing your product. This Key is nothing but your product activation key. There are 2 ways to purchase McAfee product either through online or offline. If you want to activate McAfee with product key then contact McAfee activation support.
Please read the originial post here: https://www.mcafeesupportnumber.co.uk/blog/how-to-activate-mcafee-with-product-key/