How long does it take to get a P45 for an employee that has been marked as a leaver?

Hello accounts-justint, Welcome to the Quickbooks Community page , it sounds like you may have not ran the payroll that's why the employee has not got the P45. So what you need to do is run the payroll and then finalist payroll, so that it then generates the p45 for the employee and also gets submitted to HMRC.