Many of these sites lead you to "Human Verification" screens. They ask you to download three other apps or fill out surveys to "unlock" the GTA 5 file. This is a marketing tactic to generate ad revenue for the site owner.
The short answer is . Rockstar Games has never released a native version of Grand Theft Auto V for mobile devices. apkgta5com free
If you own the game on PlayStation, you can use the free Remote Play app to stream the game from your console to your phone. Many of these sites lead you to "Human Verification" screens