Why does Apple ID always make me to put in my visa card info?

You are required to have a payment method on file, even for free content. It is used to verify your identity, age, address and country. You may be able to remove it if you never download an app that has in-app purchases and don’t have any apps that offer content subscriptions→Remove a payment method from your Apple ID - Apple Support, but you must enter one to set up your Apple ID.

You are not obliged to put it, but you can add it, to make it easier when making a purchase.