When you say that something "is required", it means that people have to do it.
Things that people often say "are required" include:
- Attendance is required.
- Registration is required. (You have to register.)
- Immediate action is required. (You have to act quickly.)
- Further research is required. (This is often used at the end of academic journal articles to say that someone needs to research a topic more.)
- A permit is required. (You need a permit, which is an official document that shows you're allowed to do something.)