How can I generate a receipt, following a completed booking, that I can use to claim doggy boarding costs following a business trip?

Hi

I frequently make use of http://Rover.com to find doggy sitters and boarders to look after my dog while I am travelling for business. I would like to be able to download a receipt following a completed booking so I can claim the expense. Could you please explain how I can generate a receipt..?

Thank you Alan