Stop your car, and stay at the scene of the accident.
Hitting a person with your vehicle is treated like any other auto accident at first. Always stop driving as soon as you realize you have hit someone. It is hard to claim that the accident was the pedestrian’s fault if you do not even notice that you hit a person.
Next, check with the pedestrian, and see if they need help. It is probably wise to call medical professionals even if nothing appears wrong, because injuries can appear nominal at the scene of the accident, but actually be severe.
Call the police.
Just like with any other accident call the police. You may not want to, but it is always wise to protect yourself from exaggeration and false accusations. The police will determine who was at fault the accident. (It is not always the driver.) They will help if anyone is injured, and they will give you a report you can share with your insurance company.
Report the incident to your insurance company.
After you have reported the incident to the police, report the incident to your insurance company. If the accident was your fault, and the pedestrian has been injured, you may be liable for their medical expenses. Your insurance company should cover your liabilities, so report the accident as soon as possible.