When you want to post code on the forums, it’s better to post it directly and not a screenshot: Using code tags properly
This error is general, and you could create a new thread for your issue (in the future, please).
It looks as though you never assign your animator variable “MyAnimator”.
You can make the variable public or use the attribute “SerializeField” and assign it in the inspector.
If it’s on the same game object, you could also use GetComponent in Awake().
Hope that helps. 