You can display infowindow message to each location using Wp Google map plugin. Follow below steps to Display infowindow message of each location:
Step 1: Go to Add or Edit Map page.
Step 2: Select ‘Display Infowindow’ radio button from ‘On Click’ tab. By default it is selected.
Step 3: Enter the Message in ‘Infowindow Message’ tab.
Step 4: Save the map and open it in a browser.
You’ll see the infowindow message on the location.