After modifying an object I deleted the camera, and after that I add a new camera to the scene but in the end I couldn't see anything with my new camera view with Numpad 0 and rendering, it just shows blank.
Can anyone help me? Thank you.
That's because the scene camera was set to the mesh itself, instead of the Camera:
Just imagine: Can you see your own face without a mirror in real world? :P
Solution is simple: Go to Scene tab (located in Property Editor), use the actual camera object instead of the default one. Or select the camera object then press Ctrl Numpad 0 to set it as the active Camera to the scene.
Another issue in this case is that the Aperture type of the camera was set to Radius, which makes everything blurry with current parameters. Or you can simply switch to F-Stop to solve the blank render issue:
Not sure what is wrong exactly with your file, some sort of glitch.
I created a new camera object, switched to it as active camera with Ctrl + 0, then switched back to your originally created camera and it started displaying correctly again.
Make sure you clear your camera objects scale with Alt + S and make sure you adjuts the clipping limits so your objects are within the visible area.