If you want to, you can use End of Year Tax Forms Assistant to prepare and e-file test data to HMRC. Test filing enables you to determine the accuracy of your data before you file an official return and to practise your electronic filing procedures. It can also help you train new employees to use the assistant.
When you submit test payroll tax data with HMRC, your submission does not update any records in the HMRC system, and you will still be able to file an official return at a later time. You can also test-file amended returns after your original return has been filed.
All responses you receive about your test submission, including error messages and notification of successful filing, will be the same as those you would receive when you submit an official tax return.