You will want to enter the amount you paid for Massachusetts Paid Family Medical Leave in Box 14 using the category "Other deductible state or local tax". This will correctly route it to the state tax forms and provide an additional state tax if you are itemizing deductions.
Entering it in Box 14 and using "Massachusetts PFML" does not work because the system considers that payment of medical leave to you is included in your wages, not a deductible state tax collected from you.
