Transform
Here is how to make 3D movement with transform.
float h = Input.GetAxisRaw("Horizontal");
float v = Input.GetAxisRaw("Vertical");
transform.Translate(h * Time.deltaTime * speed, 0f, v * Time.deltaTime * speed);
Remember to create a public float for the speed variable. Like this.
public float speed = 5f;
You can change 5f to what ever you want. Just make sure to add f at the end. Example: 10f or 15f.
And you can still do physics.
I hope this helped.