As an employer, you must report your payroll taxes to HMRC throughout the year.
Complete the following steps within Payroll
Go to the Settings tab, then select Payroll Settings.
Review or edit the following information:
Employer PAYE reference
HMRC assigns your Employer PAYE Reference when you register for PAYE for Employers. See HMRC online services.
Accounts Office reference
This is your 13-character reference number supplied by HMRC. You can find it on your P30BC payslip booklet or P30B letter (paying PAYE electronically).