You can take scanned copy of the receipt.

And simply print it for reference.

You can also download it from official website if available.

Make sure you take enough prints so it can be used for further reference and proof.

Hi !!
There is always the printing option available after the fees is payed and if it is not then you may take printing out of the screen ..as there is a print screen option available in the computer.
Hope it helps you!!