The English term comics is used as a singular noun when it refers to the medium itself (e.g. "Comics is a visual art form."), but becomes plural when referring to works collectively (e.g. "Comics are popular reading material.").

Is comic plural or singular?

The plural form of comic is comics (singular or plural in construction).

What is correct comic or comics?

"Comic books" is much more widely accepted than "Comics books." See Google NGram. "Comic books" is the more grammatically correct phrase, as "comic" describes the kind of book.