For most people, the standard mileage method gives a higher recovery with less paperwork. The standard mileage method can be used whether you own the car, or lease it, or "own it" (have title but are making payments to a bank holding a lien).
To use the actual expense method, you need much more extensive records. And, when you say financing, do you mean you owned the car with a loan, or you leased the car, or something else?
See chapter 4 of publication 463.
https://www.irs.gov/forms-pubs/about-publication-463
