Azure Information Protection (AIP) allows you to classify and add security directly to your sensitive data so that it's always protected and identifiable.

Example : 

Admin creates policies for data classification, labeling, and protection. Sally, an accountant, creates a document that has customer PII, including credit card numbers.

When Sally saves the document, it’s automatically classified CONFIDENTIAL and encrypted with permissions

When she emails the document to her team, she accidentally includes two unauthorized users. Sally’s team are able to open the file, but cannot print, save, copy text, or forward the file. The two unauthorized users are unable to open the file or forward the email.

Sally and IT can view successful/unsuccessful attempts to open the file. Sally or IT can quickly recall the document from unauthorized users.

Requirements 

Microsoft Azure Information Protection is included in the Office 365 Enterprise E3 and above plans.

Extra Licenses can be found here

You need to install the client Manually ( AzInfoProtection.exe )

You should then have the task bar and can change categories