I can’t sign into my laptop

See if the following support article can help: Change or reset the password of a macOS user account - Apple Support

I’m trying to sign in on my MacBook because my sister broke the screen so we had to get a new one but it says because i want to transfur my cloud it says i have to get on my other macbook but its broken i physically cant the screen is broken and its expensive to repair

Please start a new post. Even though you may believe your issue is similar to the OP's, it will, most likely, require a different solution. In this case, try connecting an external monitor.