I want to be able to invite a friend to start using Cake, and claim a member-gets-member referral Reward when the friend starts using Cake.

In the first implementation, we used the mobile number of users as referral identifier (which can be used amongst friends). In version 2, we will also support a generic link to be shared on social networks.

Note (from Cake): The member-gets-member Rewards is a benefits you can earn using Cake. You can find a detailed description about Rewards on the frequently asked questions page of the Cake website: https://cake.app/faq/.

I would like to add my mobile number to my profile. This will enable my friend to send me a referral Reward (using my mobile number).

In future, we might also use the phone number to...
* log-on into Cake using my mobile number (as apposed to my mail address).
* transfer money using my phone number (instead of my bank account).

Note (Cake): The "Transfer money using a mobile number" idea is described here: https://feedback.cake.app/forums/924664-open-roadmap/suggestions/38805925-transfer-money-using-a-mobile-number