Your FICO® Score is based on the information contained on your credit report at the time your score is requested.
Each month, your credit card issuer reports the outstanding balance appearing on your last billing statement to the credit bureaus. This means that whether you pay your balance in full each month or just partially, the balance appearing on your credit report for an account will usually be the balance appearing on your last statement. So, even if you pay your balance in full each month, the additional charges made since your last payment will result in a new balance that will then be reported to the credit bureau the following month.
If you want to have your credit report to show a zero balance for a particular credit card account, pay your last billed balance in full and then make no additional charges to that account during the following month. The result will be a zero balance on your next statement, which will then be reported to the credit bureaus and appear as a zero balance on your updated credit report.