Correspondence is a form of distance education, also known as "correspondence education". Correspondence courses are usually taught by letters, emails, emails and online videos. Students can teach themselves at home and consult their tutors when necessary.

Correspondence education originated at the end of19th century and is a form of distance education through letters. With the development of communication technology, modern correspondence education has developed into various forms including online video, online courses and mobile learning.

The advantage of correspondence education is that it can be easily studied anywhere, and it is suitable for people who can't attend traditional teaching classes regularly, such as full-time workers, housewives, disabled people and so on. Correspondence education can also help people get a higher education level and improve their competitiveness while working and living.