Users can contribute to Google Maps by submitting new locations, correcting existing entries, and suggesting changes to routes. To add a new location, users can drop a pin on the map and select options to add a missing place or business, providing details like name, category, and additional information such as contact numbers and photos. Edits to existing entries can be made by selecting a location and navigating through the info card to suggest changes like updated hours or location corrections. Users can also update road information and provide feedback on directions through specific features in the app. All submissions undergo a review process, but there is no guarantee that changes will be implemented.