Hello novajanine,
Thanks for posting. I know it's important to ensure your camera works as expected, and I'm happy to see if I can offer some assistance. Thanks for sharing that photo to demonstrate what's happening!
Your photo looks a bit similar to what you might see when shooting in Portrait mode: Use camera modes on your iPhone, iPad, and iPod touch
"Portrait
Portrait mode creates a depth-of-field effect. This effect lets you compose a photo that keeps your subject sharp while blurring the background. You can use Portrait mode with an iPhone SE (2nd generation), iPhone 11, iPhone 11 Pro, iPhone 11 Pro Max, iPhone XR, iPhone XS, iPhone XS Max, iPhone X, iPhone 8 Plus, and iPhone 7 Plus. If you have an iPhone X or later, you can also take a selfie in Portrait mode. Learn how to identify your iPhone."
If your Camera app is in Portrait mode, try switching to the standard Photo mode and test again.
If that doesn't help, or if you're already using Photo instead of Portrait mode, try the suggested steps here; some of these could help with what you're seeing: If the camera or flash on your iPhone, iPad, or iPod touch isn't working
Have a good day.