Knowledge articles are those who provide users with information such as self-help, troubleshooting, and task resolution.

These are the Knowledge Article States 

Draft : The article is in the process of being created.
Review : The draft is sent to reviewers to approve or reject.
Published : The article is approved and published.
Pending retirement : The published article is selected for retirement
Retired : The published article is retired. Retired knowledge articles cannot be searched for by external users or customers.

Please mark my answer as correct and close the thread so that others can also benefit.

Regards

Prasad Dhumal