To add a missing road to Google Maps follow the instructions below:
On your computer, open Google Maps.
Click Menu .
At the bottom, click Send feedback.
Click Missing road.
Click the map where the missing road should be.
Add the name of the road and any additional information.
Important: Make sure you have the latest version of the Google Maps app.
On your Android phone or tablet, open the Google Maps app .
Tap your profile picture or initial Help & Feedback Send Feedback.
Select the affected road.
From the list that appears at the bottom, tap the place or road you want to fix.
Follow onscreen instructions to send your feedback.
This feature is not available on iOS.
See the official writeup by Google here.