In the native app packages (i.e. you have a “Google App” and/or an “Apple App”), your app must be listed in the Google Play Store, respectively in the Apple App Store (so-called “App Submission”).
For this you need additional developer accounts with Google and Apple! The developer account with Google costs $25 US once and with Apple $99 US annually.
After that, your app can be published in the stores and installed by all smartphone users.