SQL Data Discovery and Classification is a feature in SSMS used to identify and tag columns in your database that may hold sensitive data, like personally identifiable or financial data. The feature can scan your database to try to identfy these columns, or you can tag them yourself. Once identified, you can run a report showing anywhere in your database that you store sensitive data.
I’ve committed a script for a test table, with customer data like names, date of birth and credit card numbers.
To start, right-click on a user database and select ‘Tasks’ then ‘Data Discovery And Classification’ and finally ‘Classify Data…’.
Using the test table, we’ll get a message that the tool found some recommendations for classification. Clicking this message will bring up a screen to display these recommendations, and we can choose which ones to accept. Or we can tag columns ourselves by clicking on ‘Add Classification’.
There are two values that we’ll assign to each column: Information Type and Sensitivity Label. Information Type includes values for ‘Name’, ‘SSN’, ‘Credit Card’ and similar types. This will let us know what type of sensitive data is being stored where. Sensitivity Label indicates the level of sensitivity, with values such as Public, General, Confidential and Highly Confidential.
Once we save our data, we can click ‘View Report’ (Or ‘Generate Report’ from Tasks) to see a report of our classified data.
This feature is available in SSMS 17.5 or later, and wil work with SQL Server 2008 and later.

Microsoft – Data Discovery And Classification