Pick Your Platform
Android players install the APK directly — the Android Guide walks through it. iOS follows a different, browser-based install process since Apple's distribution rules differ, covered in the iOS Guide. Desktop skips installation entirely; just play straight through a browser.
Whatever you pick, your account, wallet and rewards stay exactly the same — installing an app only changes how you reach 6 Club, never what's inside the account.
Matching the Platform to How You Actually Play
If 6 Club is mostly a phone thing for you, the Android APK or iOS install gives a faster, app-like return trip each time instead of typing a URL into a browser. Mostly at a desk instead? Skipping installation and using a browser is the lower-friction call, since there's nothing to keep updated.
None of this locks you in — an account started on desktop works exactly the same if you install the Android APK later, and the reverse holds too, since everything ties back to the login, not the device it began on.