Welcome to the Make community!
Make doesn’t have a module for Channels yet.
Can you find the Whatsapp Channels developer/API documentation?
If the external service has a Developer API Reference/Documentation then you should be able to integrate the endpoints in Make using the generic HTTP “Make a request” module.
I’m sure others would agree that this is a nice feature to have.
You can submit this suggestion to the Idea exchange, under App improvement ideas.
Don’t forget to search for it first, just in case someone already suggested it, so that you don’t end up creating a duplicate.