Absolutely! There are two ways to add a promotion/referral code to your account. Please note -- once a code has been added, it cannot be edited. Additionally, this can only be done from the web and not the mobile application.
1. When creating a new account, you're able to add your code during the account creation flow. Pictured below:
2. If you already created your account but have not yet funded and want to add a code, you can add a promotion/referral code from the homepage of the Dashboard! Pictured below: