Normally, the camera's focus is correctly set before being shipped. On rare occasions with normal operation, the focus may change and distort the image.
To adjust the focus, just simply rotate the round circle at camera lens, it is best to do this while 'live viewing' the camera from the app.
The other thing we recommend is checking to see that the lens of the camera is clean. If it's not clean then use a lens cleaning cloth to remove anything that might be influencing image clarity.