Usually, this is done via APK files. APK files are Android installer packages downloaded from the internet, and they're often provided by third parties like websites dedicated to hosting the files.

Sideloading APK files on your Android 12 Opening Note: We recommend that you exercise caution when installing APK files. ONLY download and install files from a trusted source like APKMirror.

[Downloaded files are stored in the file manager] Tap on the APK file to begin the installation. Once the Free Fire India is installed, open it and let the additional files download.