A clear handover starts with a timetable and the right questions.
Agree the changeover date
Speak to the people handling payroll before making a change. Agree which pay run each person is responsible for.
List the records needed
Your new provider will confirm what they need and how to share it securely. Do not send employee or bank details in a general website enquiry.
Leave room for checking
Plan time to compare the opening records and ask about anything missing before the first pay run. This is illustrative general guidance for a fictional demo.