How to disable your iTunes to be able to update apps

iTunes doesn't have anything to do with updating apps. I'm going to guess you don't have a valid payment on your Apple Account and you are seeing a message your App Store and iTunes Account is disabled. This would prevent you from being able to update apps because there is a payment issue with your Apple Account.

You must resolve that issue with Apple directly. Inside this link is a blue word link which you tap to ask Apple for help Reactivating your Apple Account --> If a message says 'Your account has been disabled in the App Store and iTunes' - Apple Support

Did you add the payment method as described in the Support Article viewed on the top of the page? You will not be charged to download free apps or update your current apps. If you currently owe money for an unpaid subscription, that will need to be paid before you can use the App Store including updating apps.

If you can’t download or update apps - Apple Support

Open settings go to AppStore turn off automatic updates.

If that doesn’t work try a hard reset if that doesn’t work backup your phone and erase it