pixiv offers a “label account” system that allows publishers to post previews and serialized works.
 

What are label accounts?

A label account is a pixiv account officially managed and operated by a publisher. These accounts are used to post official content such as serialized works and preview chapters of commercial publications.
 

About the publisher badge

Approved label accounts are given a “publisher” badge.
This badge is displayed on the profile page and other areas, including message notifications.