OnePlus provides an option to switch between 60Hz and 90Hz refresh rate on OnePlus 7 Pro and OnePlus 7T/7T Pro for saving battery life, but it requires a couple of taps to turn on and off. If you want to make the switching quickly, you can add a Quick setting tile to toggle 90 Hz to 60 Hz rate. To add a 60Hz-90Hz refresh rate switching tile on Quick settings menu on OnePlus 7 Pro, follow below steps. The 90Hz refresh rate is the default for games. Even while you in 60Hz mode, your phone will still jump up to 90Hz when you’re playing a game that can make the most of it. [Source]