They take advantage of the power of word-of-mouth advertising by offering rewards to users who spread the word about the app. This tactic helps both companies by bringing in new customers and current users byrummy money app rewarding them for referring others. Joining a refer and earn app is typically a quick and easy process that only requires a few easy steps. First, depending on your device, you must download the app from the Google Play Store or App Store. After installing the app, you'll be asked to register with your phone number or email address. Also, some apps might let you register with your Google or Facebook accounts.