At this time, you can give them your credit card.
After you pay, they will tell you some rules.
"The gas tank is full. You should fill it up before you return the car. If you do not, then we charge $3 a gallon."
"You can pick up your car downstairs. Just show them the invoice and they will have your car ready for you."
"You will need to return it by 4pm on the 16th. We charge an additional $8 for every four hours that you are late. Return it to the same place you picked up the car."
"Please keep this form in the car. Bring it with you when you return the vehicle."
The price of $8 is just an example. Make sure you find out if you are not sure you will be late or not.
"How much do you charge if I am an hour late?"
After this process, you should have your car and you are ready to drive away.