Google Play
Search the operators brand name on Google Play. Install, open, sign in. Updates are handled through the Play Store.
Android readers get the Play Store listing or the APK from the operators site. iOS readers get the App Store listing or the mobile web fallback. This page reads both paths and the small set of things that go wrong.
If the operator is on Google Play, install from there. If not, the APK is on the operators site. Both paths land at the same app.
Search the operators brand name on Google Play. Install, open, sign in. Updates are handled through the Play Store.
Download the APK. Enable install from unknown sources for the browser only. Open the APK, install, disable the toggle, sign in.
iOS readers get the App Store listing if the operator is published there, or the mobile web fallback if not.
Search the operators brand name on the App Store. Install, open, sign in. The App Store handles updates.
If the operator is not on the App Store, the mobile web app is the fallback. Add the site to the home screen for a near-native experience.