When the Pay Date is Finalised, IRIS OpenPayroll will submit all RTI returns automatically, online and on time. Use the Payroll > Online Filing screen to check the status of your RTI submissions.
KashFlow Payroll will submit an EPS automatically, but only if one is required and only after the end of the current Tax Month (but before the deadline on the 19th).
You are responsible for paying your employees their Net Pay and paying HMRC for the tax and NICs you have deducted on the payslips plus the employer NICs that you are liable for. You can go to the Company menu and select Payments and Receipts to see how much is due to HMRC.
You should pay HMRC before the 19th of the next month. For a more detailed breakdown you can generate detailed reports.