Gimbal Settings: 
Here you can adjust how your gimbal moves.
Gimbal Mode:
There are two choices Follow and First Person View (FPV).
Follow: In this mode, the camera will remain stable and maintain the horizon
FPV: This orients the gimbal with the movement of the drone. So when you change the orientation of the drone, the camera view will move with it.
Centring Camera: If you tap this then the camera will move into center place horizontally or straight down.
Adjust Gimbal Roll: You can use this to adjust the tilt of the gimbal if it is misaligned. You can do this when flying rather than having to bring your drone back to fix it.
Gimbal Auto Calibration: The drone will automatically try to center the gimbal, this must be done when the drone is on a level surface.
Advanced Settings:
Here you can set gimbal functions.
Gimbal Pitch Speed: This controls the speed at which the gimbal tilts. A higher value means a faster-moving gimbal and lower value means a slower gimbal.
Enable Upwards Gimbal Tilt Limit to 30 Degree: Turning this off will allow the camera to tilt up beyond 30, but you’ll be able to see the propellers in any shots you take. Unless you are flying backward.
Gimbal Pitch Smoothness: This controls how quickly the gimbal will come to a complete stop after you move it. A lower value means a quick stop and a higher value means a slower stop.
Enable Synchronized Gimbal Pan Follow: Enabling this makes the camera move with the yaw stick. This helps videos to be smoother when you move the yaw stick.
DJI GO 4 Manual Contents:
Image Transmission, Battery, Wifi & Virtual Joystick Settings