why I can’t get free apps or update free apps without my credit card

If you don’t set up an Apple ID from the onset, to not use a credit or debit card, you have to enter one in order to make purchases. After you enter a card, you may be able to delete it and just use iTunes gift cards or just download free content.

This is how you set up an Apple ID without having to use a credit card.

Create or use an Apple ID without a payment method - Apple Support

Hello Jackiedrust6581, 

If you're having issues regarding iTunes & App Store you may contact iTunes Support.

If you try to update/download an app and it asks for update or something related to your payment method there's a pending charge maybe and you wont be able to get any app even it is free unless you pay for pending charges on your account.

https://support.apple.com/en-us/HT204088 <-- Review your purchase history

https://support.apple.com/en-us/HT201232 <--- Support phone numbers according to your region

https://support.apple.com/contact <--- You can chat with an Apple Care advisor as well

Regards.