If you do a search on-line, you can find purchase agreements to suite what you are looking to do. Review, print off and follow the instructions to a “T”. With the title, do as said above.
This can be a very effective way to sell a car that is not selling, help out a friend or a way to get some more money out of the deal. I would not be doing this for free. Interest, set fee or gratis should be in order, unless it is your son or daughter. That would be up to you.
I will add I do not sell vehicles to friends though
. I am on the hook for any issues that always come up