Seeing MacBook password
In most cases, no you can’t get at the plain text password on macOS. 

In one case, if you know the keychain password and it’s different than the log in password, unlock the keychain and look to retrieve the Mac password from any item where it’s stored. 

The only way to reverse engineer would be to obtain the password hash and crack it brute force. 


What type of hash are a Mac&#39;s password stored in?


You can always make a new admin account or write over a new password, but that will change things since you don’t know the current password. 


https://support.apple.com/en-us/HT202860