From Wazeopedia
grammar update
When moving a house number or adding one, you will see a dashed white line leading to a white dot on the road you selected. This white dot is the Stop Point for navigation to that house number. It can be moved anywhere on the named segment for that address. It cannot be moved to any other segment.
The Stop Point should be placed where you would park if you wanted to park closest to the main entrance to the building, driveway, or an entrance to the building parking lot. Think of it this way: "If you can get an end user the driver to this point and tell and have the app display a directional marker flag and announce the correct side of the roadthe destination is on, the driver should be able to figure out which building it is."
Note: if you have aerial images turned off, such that the background screen is white, you will not be able to see the dashed line. Because it's white.