Most fast oil change places work the same way.
You drive your car through the facility, which has a pit in the middle that can easily hold a person who is standing up without the car hitting them.
The person in the pit removes the plug from the oil pan and collects the used oil (4–5 quarts) into a recycling tank (it will be sent to a refinery to make new products).
Up top, another technician removes the oil filter and puts on a new one.
Once the oil drains, the technician replaces the plug and advises the technician up top, who starts to re-fill the oil reservoir with 4–5 quarts of the chosen oil.
After it’s refilled, the technician checks the dip stick to make sure the oil level is correct, and you’re done.
This can very much be a do-it-yourself project, but the tough part is getting under the car to remove the plug and to collect the oil as it spills out. You also have to return the used oil to a recycling facility.