This visa is for a person between 4 and 17 years old who among other things has an offer of a place on a course with an accredited UK organisation, had their guardian consent, and can support themselves financially.
This visa for parents may be valid for 6 or 12 months and the parents need to apply for 12 months at a time until the child turns 12 years old.
You would need the reference number also known as “confirmation of acceptance for studies” (CAS), which you would enter on your visa application.
You would also need to submit such documents for the child as ID, financial evidence, consent of legal guardian and medical results of a tuberculosis exam in certain instances. The parents would need to submit similar documents for themselves.
You can extend this visa to continue the course if you still fulfil the requirements.