How to turn off the mobile phone camera when taking pictures?

You can turn it off in the phone settings.

First of all, you can start with the software, uninstall all camera software, and refuse other camera use rights that may use camera software.

There is another way, you can use transparent tape, vaseline and other objects to stick to the lens surface, so that even if you turn on the camera, you can't see anything clearly, and you can also code globally to protect your privacy.