What is a PhD. in rhetoric and composition? What can you do with it?
Rhetoric and composition is about writing (and sometimes, verbal communication more broadly). The difference between a PhD in English (literature) and a PhD in rhetoric and composition is kind of like the difference between majoring in English (literature) and majoring in writing; the “literature” is nearly always implied after the “English.” In an English literature program, you’d be studying and doing research on literary works written in English. In a rhetoric and composition program, you’d be doing research and scholarship on writing and discourse.
The ‘traditional’ route for a PhD in rhetoric and composition is to teach college-level writing and do research on writing as a professor. Rhetoric and composition professors may teach required freshman composition classes as well as higher-level writing classes in departments that offer them. Other jobs may include working in (or directing) a university’s college writing program or writing center or working in academic affairs in other capacities (like academic advising or student learning support). Some PhDs in rhetoric and composition may go non-academic and get jobs doing writing and communication work for nonprofits, NGOs, government agencies or for-profit companies. Those would vary widely (and you don’t need a PhD to do them).
I’ve heard that rhetoric and composition PhDs have marginally better chances on the job market than English literature PhDs. However, the humanities academic market is tight all around.
You could potentially teach ESL or introductory English. However, keep in mind that the academic market is awful (as the above poster noted). There are adjunct positions to be had, but very few full-time positions. Best case scenario = maybe a director job @ the academic writing/tutoring center in combination with teaching duties, a job in the K-12 system, or working in a communications role at a non-profit.