Can add cash to my account from my bank account

Apple currently accepts the following payment methods.

• Apple Card
• Apple Pay
• Apple Cash
• Most credit and debit cards
• PayPal
• Apple Account balance (from redeeming Apple Gift Card or adding funds)

You can view the full guide here: Payment methods that you can use with your Apple ID - Apple Support

Are you trying to add it to your Cash Card?

Is your account currently set up to pay off the Apple Card?

What errors are you getting?