my ipad air is disabled,how can i fix that

See 'Your account has been disabled in the App Store and iTunes' https://support.apple.com/en-us/HT208856. This link says: "There might be a problem with the payment method that you have on file. When you see the message, don't try to edit any of your account information. Instead, contact Apple Support for help.”

Use the Apple recommended support link above first.

You also can use Apple Support Twitter https://twitter.com/AppleSupport

And, if necessary, go here is how to contact iTunes worldwide support via text or chat using this link https://support.apple.com/choose-country-region/itunes After choosing your country, see the heading Tell us how we can help.

See instructions in If you forgot the passcode on your iPad, or your iPad is disabled - Apple Support

my apple ipad says ipad disable connect to itunes

See my reply above.