Step 1: In order to enable the privacy plugin that is loaded with Joomla 3.9+, you will need to be logged into the Joomla Administrator Dashboard. Log in to Joomla with your Administrator user.
Step 2: Click on Users in the menu at the top of the screen
Step 3: Scroll down the menu until you see Privacy and click on it.
Step 5: When you are done with the messages and settings, go to the top of the page and click on either the Save or Save & Close optons.