How to enable text messaging

Welcome to Android Central! What do you mean when you say you accidentally disabled it? Do you mean that you disabled the app itself? If so, then go to System Settings/Apps/All, and scroll all the way to the bottom, where Disabled apps are listed. Find the "Messaging" or "Text Messaging" app (the name may differ with each device), select it, and tap "Enable."

If you disabled the actual texting service through your wireless provider, then you'll need to talk to them to reenable it.