What does zero balance mean?
Pertaining to credit card related terminology, when you have zero balance on your monthly statement, you do not owe towards the credit card company. But having no debts at all, it means that you cannot show up a good and constant credit history; if you have no balance, you don’t have to make repayments, so your credit report in that sense does not show activity.
Cards which have a zero balance may be left open; however you may incur penalties for canceling it. The best way to keep that good credit rating is, pay your balances in order to minimize them, and at the same time try to keep your credit limit at a high value, because that will definitely add to your credit scoring.