We have already talked about usability and its fundamental importance to ensure that users do immediately after downloading it. But UX does not only mean attention to the design of all the elements, but also means considering (and above all) the ease of use.
No to overly complicated steps in the normal use of the malaysia phone number example application and absolutely no to asking for too much information during registration.
Especially at the initial stage, that is, when downloading the app, the user must feel motivated to use it and manually entering too much data can be really demotivating.