how to add force using a rigidbody code example

Example 1: how to make rb.addforce 2d

public Rigidbody rb; //make reference in Unity Inspector

public float SpeedX = 0.1f;
public float SpeedY = 0.5f;

rb.AddForce(new Vector2(SpeedX, SpeedY));

Example 2: rb.addforce 3d c#

rb.AddForce(0, 0, 5 * time.deltaTime);

// time.deltaTime is optional