MacBook locked find my mac

Is this your Mac? If it isn't and you've purchased it 2nd-hand or acquired it some other way then you have to ask the original owner to release it from Find My using their AppleID.

If you have no access to the original owner then you've got a real problem as well as a computer that is useless to you: How to remove Activation Lock – Apple Support (UK)

You have to go in privacy and Security in System settings, go on privacy service and System settings, than you have to click on find my Mac