Add component object to gameobject unity

//to add a new ridgidbody
gameobject.AddComponent<Rigidbody>();
//to add a new meshCollider
gameobject.AddComponent<MeshCollider>();
//Original answer by MakerBenjammin6, cleanup by me.

//referencing a gameobject
public GameObject exampleObject;
//===============================================================>
private Rigidbody rb; //example of a component

public void Awake() {
	// adding a Rigidbody component to exampleObject
	rb = exampleObject.AddComponent<Rigidbody>();
  
	// referencing an existing Rigidbody component in exampleObject
	rb = exampleObject.GetComponent<Rigidbody>();
}

//This uses C# and unity
//to add a ridgidbody
gameobject.addComponet<ridgidbody>();
//to add a meshCollider
gameobject.addComponet<MeshCollider>();
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void Reset()
{
  //Your code here
}