How to have a form auto fill

I would like to know how to show data in a form that was updated from the last time a form was submitted. I am trying to create a form for tracking when someone needs to change oil in a car. I would like to have a field that someone would input their next oil mileage need. And each time they open the form it would show the mileage that they inputed the last time they inputed oil change mileage. How do I do this