Sometimes you need to allow a user to access and manage only one (or a few) Joomla! component in the backend. This is quite easy to set up, you need to use cleverly the ACL sytem Joomla has allready in.
Indeed, what's needed for a user to submit a new content item from the frontend, and how he/she should proceed?
First of all the user must have the privileges corresponding to the authorization level of "author" or above.
Also known as two step-authentication or two-step verification, two-factor authentication is an additional security option for online accounts to help keep them safe.
A client of mine asked this question: "How can I allow registered users to log in and see the site even in offline mode, without giving them Super user privileges?"