Add Axene to any Make scenario with a single HTTP module.
In your scenario, add an HTTP, Make a request module with method POST and URL https://mail.axene.io/v1/emails/.
Add an Authorization: Bearer axm_k_live_... header and a JSON body with from, to, subject and html.
Map fields from earlier modules into the body and run the scenario.
A native Make app with ready-made Axene modules is on the roadmap.