Hi sergiu116,
We understand your camera is not working properly. We're happy to offer some guidance.
If the camera is not working properly, you can try these basic steps: If the camera or flash on your iPhone, iPad, or iPod touch isn't working
Based on the image you attached with your post, it also looks like the picture may have been taken in the dark or low lightning conditions. It's also a good idea to test the camera in a brighter area to see if the camera just isn't getting enough ambient light in your current location.
If you are in an area of dim or no lighting, you can also use the the Night mode function in the camera and change the exposure length. The longer the exposure length, the more light the camera lens will be able to pick up to make the picture brighter.
Use Night mode on your iPhone
If you continue to have issues with your camera, we'd recommend contacting Apple for assistance: Get Support
Hope this helps. Cheers!