reactivate account

If you had Apple deactivate your ID, from the article below.

Can I reactivate my account?

Yes. If you request account deactivation, you'll receive a unique alphanumeric access code. When you're ready to reactivate your Apple ID, contact Apple Support, provide your access code, and we’ll help you reactivate your account. If you lose this code, we won't be able to help reactivate your account. 

Apple ID - How to deactivate your Apple ID account

If you mean the account is locked : If your Apple ID is locked or disabled - Apple Support

Or disabled : If you see a message that says 'Your account has been disabled in the App Store and iTunes’