How to hide savings account info in Apple Card wallet

Hiding an individual feature is not possible. However you may be able to hide the Wallet app following the steps in the Apple Support article linked below.

Lock or hide an app on iPhone - Apple Support

You cannot.

What kind of hiding do you want? It’s almost impossible to gain access to Apple Wallet without your face or passcode. Do you frequently hand out your passcode?

Im curious what you want for hiding your account? iOS 18 allows you to lock Apps and Folders. But hiding is a little harder and comes with much more severe consequences.