Line Webtoon (originally Naver Webtoon) is a free webcomic host. The site features webcomics as well as digitized comic books.
However, Webtoons doe occasionally has comics that are more appropriate for an 18+ audience, but those comics are usually not featured on the front page or in their "Featured" section and always have a notice on the page warning users before they can read the comic.
Webtoons comics are divided into "Featured" and "Canvas" sections on the site:
Comics in the "Featured" section are officially endorsed by Webtoon. Featured comics must be approved by Webtoons' editorial team beforehand and featured comic creators receive guaranteed rates and bonuses, but featured creators cannot post their comics anywhere else online once they agree to have their comic featured. Featured comics usually update weekly, and are displayed on the front page of the website on the days they are scheduled to update. Comics in this section tend to be of high quality, and may also include animations, music, or sound effects.
Once a month, the editorial team selects popular titles from the Canvas section to promote in their Featured section, usually through a contest. Comics that are chosen require their creators to remove their comic from the Canvas section, and then the comic is re-posted in the featured section -- sometimes with modifications -- starting from the first chapter or "episode" of the comic.