The status of the underground tanks, and how full they are, is monitored over the Internet.
Resupply is coordinated through the Internet to the supplier, whose trucks, incidentally, get their fuel, from distribution set up the same way as your local gas station.
Fuel trucks are routed via the Internet to those locations that, according to the Internet, sensors show they need filling.
Many years ago, I had a teenage job at a gas station pumping gas for customers. I had to open the tanks every night after closing and write down how full/empty they were, on a log that the owner would view the next morning and call the supplier to order a shipment of new gas. The stick I used was a specially made long "yardstick" that they don't even make any longer.
You too. You’re aging yourself. I did that too when I was young. I lived right next door to a gas station and spent much of my misspent youth sitting around with the old guys listening to stories an 8–10-year-old kid should probably not have been listening to, but I digress. I learned to check oil, pump gas, wash windows, run a cash register and dip the tanks before I was in middle school. Some of the best times of my life.