You don't need a Microsoft Account
When you setup a new Windows computer you will be prompted for a Microsoft account. At first this sounds a bit draconian, well it did to me, but it is not a problem. If you have a Hotmail or Outlook email account then you can use that. If not make one up.
Or you can use a "Local Account", see link below. I didn't do this as I used my Hotmail account and am also seeing how the mail app workson my new computer.

In many cases it is quicker to just create a "dummy" account just to stop Microsoft "nagging" you, but then not use it.
The Microsoft "Local Account"
There seems to be much controversy with regards to the Microsoft Account.
The Microsoft help says: