You don't have an account limited to downloading free apps, so you must provide a credit card in the event you download apps that are not free.
If you did not create your Apple ID in the method to do without a credit card, then you need to add a credit card to your account. That is how Apple verifies your identity. If there is no payment method entered, you cannot even download free apps, as your account is not complete. If you don't have a method entered, you will have to do that. If you do and it is out of date, you will need to update it. Or, you can purchase an iTunes card somewhere and load that.