Assalam o alaikum shiekh, Is it permissible to buy car on financing with 0% rate added to final price of it and the dealer owns the car and financing from their company instead of some bank. And what if some other car have some percentage included than 0% in final price does this consider riba?

Take it as a rule. If the dealer genuinely owns the car and sells it to you on installments, it is allowed even if the installment price is higher than the cash price, as long as the total and the installments are known and fixed at the contract and nothing is added afterward for late payment. This is a sale, and a sale at a higher deferred price is not riba. But if the reality is that a party lends you money and you repay it with an increase, or the financier has not actually taken ownership of the car before selling it to you, then that is riba.