Hi Kartamish,
Thanks for using Apple Support Communities. Since the alert you've received mentions Split View, let's start there. To close split screen, use these steps from Close split screen or a floating app on your iPad - Apple Support.
"How to close or get out of split screen on your iPad
- Touch the controller in the middle of the vertical bar between the two apps.
- Drag the controller off the screen in the direction of the app that you want to close.
Learn how to use Split View multitasking mode to work in two apps at the same time."
If you continue to have any issues, make sure that your apps also have access to your iPhone camera. This guidance is from Control access to hardware features on iPad - Apple Support
"Review or change access to the camera, microphone, and other hardware features
- Go to Settings > Privacy & Security.
- Tap a hardware feature, such as Camera, Bluetooth®, Local Network, or Microphone.
The list shows the apps that requested access. You can turn access on or off for any app on the list."
All the best.