With the strong growth in the use of smartphones, app usage has also greatly increased. Therefore, mobile marketers have increasingly taken advantage of smartphone apps as a marketing resource. Marketers aim to optimize the visibility of an app in a store, which will maximize the number of downloads. This practice is called App Store Optimization (ASO).
You will have a greater chance of gaining access to their mobile number by following these guidelines. You can collect their numbers using a sign-up sheet at your register, asking them when talking on the phone, allowing them to submit a form on your website, or by giving them a number that they can text to subscribe to your SMS messages. Whatever you do, keep a copy of their permission to market to them via SMS, if you run into problems you will be glad you did.