Step 1: Head to the Google Play Store/Apple App Store.
Step 2: Search for the game Apex Legends Mobile. Then,
Step 3: Seek for the official game from EA(Electronic Arts). And open it.
Step 4: Click on pre-register. And you might get a prompt asking ‘Install when available’.
Step 5: That’s it now you have successfully pre-registered yourself for the game. Now it will download itself and install when it will launch.