To tell you the truth, I donu2019t have an account in amazon.com.First, about the address 1 portion, it can be found online stating that address 1 is where you put you house number and street address. As for address 2, you may or may not have to put additional information such as for apartments/condominiums/studio units and etc of which level.Second, as some have stated that address 2 is optional. Some stated that it is just when your address is too long and cannot fit in address 1, you might continue typing it in address 2.Third, some stated that address 1 and address 2 is where people will write down both of their address and stating that you have to send the package to address 2 instead of address 1.Commonly is the first one. I am not sure it helps. To clarify this, you may ask at its official website support team. Or you may wait for the next person who will answer this question.