Hello and welcome.
A MacBook A1181 can be one of several revisions:
MacBook (13-inch)
MacBook (13-inch, Late 2006)
MacBook (13-inch, Mid 2007)
MacBook (13-inch, Late 2007)
MacBook (13-inch, Early 2008)
MacBook (13-inch, Late 2008)
MacBook (13-inch, Early 2009)
MacBook (13-inch, Mid 2009)
Those models run versions of OS X/macOS from 10.4.6 Tiger to 10.11.6 El Capitan, depending on the model/hardware.
-Can you tell us the exact model that you have? You can enter the serial number here:
Check Your Service and Support Coverage
-Do you know which version of OS X/macOS?
-You purchased it used with a password on it, correct? Is it a 4/6 digit firmware password that you enter when powering on, or is it a user password prompt at a login screen?
-Have you been able to use the MacBook at all since purchasing it?
C