Sometimes it's necessary to add an author to a post, but without actually giving them full access to the admin portions of your site accessible by the site owner, and staff members.
To help with this, you can invite a user and give them a role of Author. After adding them to your site, you can add them as an author to a post. Once added they will be able to access this under /authors/posts.
Invite the user and give them a role of "author".
After they accept the invite, create or edit a post, and add them as an author.
They should see the post under authors/posts, and will have access to edit the title, excerpt, and image for the post.