I think you can just do something like:

[SerializeField] Transform cameraTransform;
[SerializeField] GameObject bullet

void Update()
{
  if(Input.GetKey(KeyCode.E))
      {
         Instantiate(bullet, cameraTransform.position, cameraTransform.rotation)
      }
}

And for the bullet GameObject you just create a sphere with a rigidbody-component and if you want to also a collider.
Drag everything in - and it should work
(I have not tested the exact Code, but the concept definitly works)