If I finance a car for a certain number of years, can I pay before the time. For example can I pay a car in two years when the finance was for 5 years?
Certainly ... however some loans come with a "pre-payment charge" most however don't
Absolutely. You can make as many payments as you want.
If you double or make a higher payment than is due ... they simply credit that to the next payment and do not re-amortize the loan, Buy paying ahead you gain nothing until the loan is completely paid off. They get to keep your money while charging you interest on their money. Best thing to do is put your money in the bank until you can pay it off ... then they have to refund the pre-paid interest they charged you ( they charged you 5 years compounded interest loan