I disagree with Lutfij. While the statement is sorta correct it doesn't explore all legal avenues open to owners of 10. A wee bit shortsighted it is.
https://www.tenforums.com/tutorials/5387-how-tell-if-local-account-microsoft-account-windows-10-a.html
Check if You are Signed in with a Microsoft account or Local account in Settings
1. Open Settings, and click/tap on the Accounts icon.
2. Click/tap on Your account on the left side. (see screenshots below)
If you see an email address under your user name at the top on the right side with a Manage by Microsoft account link under it, then you are signed in to Windows 10 with a Microsoft account.
If you see the words Local Account under your user name at the top on the right side, then you are signed in to Windows 10 with a local account.
You should link your version of 10 with M$ if it isn't already. M$ makes it easy to re-activate without having to buy another license.
https://support.microsoft.com/en-us/help/20530/windows-10-reactivating-after-hardware-change
Don't know your product key(key should be on a sticker on the PC's back panel or maybe on the side)?
https://www.piriform.com/speccy/download can tell you. Once you have it running go ahead and click on Operating System. There you will see that which you seek.