In the text resource we can add the html code but in the policy action we can not add it 

yes we did all the steps you mentioned above but still we could not add the message 

 Thank you for your response, We did your recommendation, but why we cannot add the HTML template? It does not appear; all the list in here is the notification template as shown below.  

after that how we can activate the HTML notification so the end user can receive the messages