Hi @Isamara Morais !

Are you looking to create a Template for Proactive Support messages such as a Post message? If so, that’s only possible for Emails. 

That said, you could create a Post message (or a Chat or any other message) that acts as a Template. You could save it in your workspace and use it as the basis for future messages - making a duplicate copy of it and then adapting the copy to your liking before setting it live. Hope that helps!