Each course is different, some list prerequisites—expecting learners to already be proficient with certain knowledge and/or skills—but many don't. Before enrolling in a course or program, you should carefully review all of the information available on its Course or Program About Page, which will explicitly list any required or recommended prerequisites.
In general, MIT Learn courses almost never require prior completion of a specific course from a specific source. The term "prerequisites" almost always refers to knowledge and/or skills that a course will assume learners already possess—from any source. However, some multi-course programs are specifically designed to be taken in sequential order, and some programs employ capstone/comprehensive final exam courses, which can only be taken after the program's other courses.
All academic materials necessary for the completion of a course will be provided by the course, within its Courseware. Some courses may also list additional optional or "recommended" resources—for example, textbooks. If you are looking for supplemental reading materials during the course, you can post a question in the course discussion forum to ask your classmates and course staff for suggestions.