Below is workflow diagram explaining the life cycle of a Knowledge Base article.
Refer to the KB Article What is your KB Article Role for explanations of each role in the diagram below.

Set KB Status & Visibility
Change state of KB to Draft, Not Submitted, Published, or Archived.
The Status of an knowledge base article is where it is in the publishing queue.
View Article Status
View the status of the article from the search results.

Change Article Status
Also view the status when viewing the article directly.
To change the status of the article, click Edit Article > Settings > Go to the Status drop-down menu.

Not Submitted
A new article that is draft or a work-in-progress can be placed in draft.
Submitted
A draft article can be submitted for review after it has been written.
In a submitted state, the article draft is still available for editing and is not public.

Approved
A new article that has been reviewed and is ready to be published the first time.
Rejected
A new article may be rejected if it has content to be fixed before being published for public view.
Archived
Move an article out of the active knowledge base while retaining it for future reference.