Do you have to have a credit card to open an apple id?

Generally speaking you need a payment method.

See  Add funds to your Apple ID https://support.apple.com/en-us/HT208687

"Before you can add funds to your Apple ID, you must have a valid payment method on file. Learn about the payment methods that you can use with your Apple ID. ... See how to Add funds to your Apple ID https://support.apple.com/en-us/HT208687  Note that "after you authorize the payment, the funds ... [are credited] to your Apple ID. Then, you can use the credit to make purchases from the App Store or iTunes store. Need more help? Contact Apple support for help here: Get started."

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But, also see Create or use an Apple ID without a payment method  https://support.apple.com/en-us/HT204034 and

If you can't remove your last payment method or use no payment  method with your Apple ID https://support.apple.com/en-us/HT203905