What is the ruling on working for and earning a salary from a car dealership that sells for cash, direct installments, and through financing from usurious banks, knowing that the nature of the work involves completing the car's paperwork in the owner's name and handing it over to him? And what is the ruling on sending customer data to commercial insurance companies to obtain an insurance policy?

There is no harm in working in the company's documents department, even if some transactions are conducted through banks, as long as you do not intervene in them, and you will not incur sin because of that. As for assisting a customer in securing his car, it is not permissible if the insurance is commercial, due to the Almighty's saying: "And do not cooperate in sin and aggression." It is permissible if the insurance is based on mutual cooperation (Takaful). In general, your work in the field of documents is lawful (halal), and your salary from it is lawful, but you must refrain from any unlawful work that is requested of you, otherwise you would be sinful and the corresponding portion of the salary would be unlawful.