PUBG Battlefield is the heaviest version of the mobile game at the moment, PlayerUnknown's Battlegrounds Mobile. The game is almost identical to the PC, and because of that, quite heavy.See how to change the game's graphics, making it lighter, or else, putting it on the ultra.
Observation: Setting from Medium to High or Ultra requires you to restart the game.
Step 1. At any time during the game, tap the gear in the upper right corner of the screen.
Step 2. Choose the second option in the left corner of the screen.
Step 3. In the image below, you can find the translation of the graphics configuration menu. some options are not enabled for all smartphones. For example, the ultra.
Some explanations about the graphics configuration:
By lowering the frame rate (leave it locked at 30 on "low") you improve the overall performance of the game. Some settings like High and Ultra are not available for all phones and tablets. There are also Ultra settings that allow you to make the game even more realistic.