Can I sell my house to a friend without a real estate agent?

My house is paid off and I want to sell it to a friend without a real estate agent involved. He will be doing a payment plan. What steps or paperwork will this transaction consist of (California)?

Yes, you can do this, but it's the worst financial mistake you can make, no matter how good a friend is. It is better and wiser for you to do this properly and legally through a deposit so that he can be qualified by a bank.