Note: This feature is only available for publications. If you've created a Substack from your profile and do not have a publication, your Substack won't have this feature.
If you'd like to add multiple authors to a byline on your post or add a different author other than yourself, you'll need to first enable bylines for your publication.
Head to your publication's Settings page and click on Branding in the left navigation bar. In this section, slide the toggles next to "Show bylines on posts" and "Show byline photos on posts".
To disable bylines on posts, slide the toggles to the left in this section.