If you want to send email notifications when a new content is published, For this to achieve you need to install rules module, this rules module depends upon token and entity modules. Install those dependency modules and activate them.
- Go to Configuration-> Workflow->Rules.
- From that page, click on the add new rule.
- On the Next Screen, Enter the Name and from the React on event select After saving new content and click on save.
- After that it will takes you to this screen, from the actions section click on the add action button.
- From the list of Select the action to add, select Send mail to all users of a role, then click on continue.
- From the next screen, select the role that you want to send the mail, and the SUBJECT line, and the Message body, and also from address, you can also use replacement patterns.