Apple’s new Maps app has numerous incorrect or missing data. The only way for Maps to be better is for the missing info to be updated and error corrected. You can help out Apple by reporting problems directly from within the Maps app.
Swipe up the options for map, on top of the “Print” button is a small link to “Report a Problem”. Tap on this text link will bring you to the “Report a Problem” screen. Proceed to provide more info to Apple.
If the error is for a particular location pin, you can tap on the “Report a Problem” button from within the location detail screen.