Do I Need My Own Formula to Manufacture a Private Label Cosmetic Brand in Korea?

Hi everyone! We’re looking to develop our own cosmetic brand and manufacture the products at a Korean factory. For those who have experience with Korean cosmetic manufacturers, do we need to have our own formulas ready before approaching a factory? Or can Korean manufacturers help with formula development and product formulation based on our desired concept and ingredients? I’d really appreciate any advice or recommendations on how the process usually works in Korea. Thank you!