You can display tooltip message in region, marker and text map using WP Geo map plugin. Follow below steps to display tooltip message of each location:

Show Tooltip Message

Step 1Go to Add or Edit Region Page.
Step 2Enter the Message in ‘Tooltip Message’ tab.

Step 3Click on Save Region and open it in a browser. You’ll see the tooltip message on the location.

Live Example Show Tooltip Message For each Locations

World Map With Capitals

Video Tutorial