We offer a way for you to provide custom text and HTML for emails. But, we don't offer a way to pass in Mailgun specific options e.g. which template ID to use (if that's what you are asking about). This is something we'll improve in the future: https://github.com/wasp-lang/wasp/issues/1553
Right now, when defining an email sender, and when sending an email via it, we don't allow any provider-specific options. It would be useful to provide some, because for example, users using Se...