If you have a business, you can go to Google Maps and add your business. Just click, fill out a few text boxes, and add.
However, scams also use this to make it look as if they really exist. They add street addresses to their fake sites.
So Google has a team of people who visit locations to see if the business really exists. These people are called Google Mappers.
This is yet another example of how Google uses a manual process to verify the information in Google search results.