When you are buying a brand new computer having Windows 10 and trying to install Windows 10 via connecting to the internet, then Windows 10 force you to use Microsoft Account to complete the setup process. It is owned by Microsoft.Microsoft and Gmail core levels both are the same. Like Gmail Account, Microsoft Account is also an email account having an email address and password that is used to connect outlook, Hotmail, Live, MSN account, MS Office, One Drive, Skype, Microsoft gaming consoles like XBOX, Windows Store, etc.