The Receipt Capture feature is currently being offered in selected regions. Can you tell us what type of subscription you have and the country you're in? This is for us to check if it's available in your area.
In the meantime, you can manually attach a photo of the receipt when recording your expenses. Here's how:
Click the + New button and select Expense, Pay Bill, or Check.
Go to the Attachment section and click the Clip icon.
Look for the receipt that you saved in your pc and click on it.