Revenue and Customs require businesses to register with their online submission service. PAYE and payroll records needs to be put in order if they aren't already, and finalised. Forms P14 and P35 (the Employer Annual Returns forms) need to be filled in and submitted over the internet. Because PAYE is an approximate system, refunds or further payments might be required.
A payroll solution needs to be put in place for the new financial year. Wages may well have changed a little over the year, or PAYE tax rates and bands shifted, so new rates need to be worked out and checked. Revenue and Customs need to be notified of your intended system for the coming year, too.
Employees may need to have a P60 generated for them and issued to them. We can tell you who needs to have one and arrange it - it's all included in the payroll services packages.