Error CS0117 Unity is not recognising a definition for .Addforce

void FlexedUpdate()
{
float moveHorizontal = Input.GetAxis(“Horizontal”);
float moveVertical = Input.GetAxis(“Verticle”);

	Vector3 movement= new Vector3(moveHorizontal,0.0f,moveVertical);

	Rigidbody.Addforce(Vector3);
}

}

You need to use references and correct misspelling.

private Rigidbody thisRigidbody;
private void Awake()
{
    thisRigidbody = GetComponent<Rigidbody>();
}
//and then anywhere you need it:
thisRigidbody.AddForce(bla bla bla);

For your example it will look like this:

void FixedUpdate()
{
    float moveHorizontal = Input.GetAxis("Horizontal");
    float moveVertical = Input.GetAxis("Verticle");
    Vector3 movement = new Vector3(moveHorizontal, 0.0f, moveVertical);
    thisRigidbody.AddForce(movement);
	//or remove movement variable at all and just thisRigidbody.AddForce(new Vector3(moveHorizontal,0.0f,moveVertical));
    //or even less coding - thisRigidbody.AddForce(moveHorizontal, 0.0f, moveVertical);
}