When you successfully file a return using TaxCalc, you'll get the following receipt. This contains the IR Mark (top left) and is your proof of filing.
You can print this receipt for your records or save it as a PDF. To do this, click on Print this FBI receipt.
NOTE: You'll also receive an electronic receipt in the form of an automated email from HMRC Gateway. However, you can't use this as proof of filing as it doesn't include the IR Mark needed to track the submission.
If you need to go back into a tax return to print a receipt, follow these instructions: