If you're using navigation, tap the Car icon at the bottom of the screen when you're near your destination. It'll stamp the time and address of the location on the map. There are options to add a photo, note, and even adjust the location in case it is incorrect. When you're done, tap the save button.

When you're not using the navigation, follow these steps:

1. Tap the hamburger menu
2. Tap Favorites and then Add location under Car