Q: hi i cant seem to attach my child toy account i dont own a credit card what can i do

To be able to create a child account you need a payment method that is only available to adults, due to child online protection laws : Family Sharing and Apple ID for your child - Apple Support

Before you begin, make sure that you're using a credit card or UnionPay as your iTunes Store and App Store payment method. To comply with child online privacy protection laws, you will use the CVV, verification code sent via SMS, or security code from a valid payment method as part of providing your parental consent. If the card on file is a debit card or another payment method, you’ll be asked to provide a valid payment method before you can continue. After you create the child's Apple ID, you can change your payment method.

The 'valid payment method' link on that has :

To create an account for a child under 13* in Family Sharing, you can only use the following payment methods:

• Credit cards
• China UnionPay
• A post-paid mobile phone billing account

After you create the child’s Apple ID, you can change your payment method to a different method, such as a debit card, China UnionPay debit card, or a pre-paid mobile phone billing account.