While you cannot "install" the game file on your phone, you can play it via or cloud gaming services:

It is helpful to look at why a native, full version of GTA 5 cannot simply run as a standard app on your phone right now.

You can play your Steam/Epic Games copy of GTA V on your phone using GeForce Now.

A browser-based service where you can play the game via Safari (iOS) or Chrome (Android) by connecting your Steam or Epic Games account. Remote Play (Requires Your Own PC or Console):

If you decide to ignore the warnings and download a GTA 5 APK from a third-party site, you are exposing your device to significant risks: