The referral code is only for new users who have no uploaded any receipts.
On Receipt page
When you first sign up to ReceiptJar, go to the Receipt page, and you will see a button where you can enter your code.
How to use your Referral Code:
Open the App;
"Receipt" tab;
"Enter Referral Code";
Type in your referral code BRITACMDJ and submit;
Done.