How to close a topic?

Can normal users mark a topic as closed? I think this would be beneficial especially for Beginner’s Questions so that people can see what has been answered and what has not.

I have read up a little on Discourse, and found this regarding the lock icon, but not how to do it:

Also, since only a lock icon is added for identifying closed and archived topics, should the user prepend [Closed] to the topic title before it can be closed?

Any thoughts?


I have proposed a plugin for this, takes some time to install it though