Ipad Is Showing Wrong Apple ID in App STORE.

Apps are FOREVER tied to the Apple ID they were downloaded under. It's almost always a mess when you change your Apple ID. To avoid this mess, you should delete the apps downloaded under the previous ID and redownload/purchase the apps under your new ID. Otherwise, you will have to sign out of the current ID and back into the previous ID every time one of those apps downloaded under the ID you no longer use need to be updated.

You delete the apps you downloaded under the previous ID and download/buy them under the new ID. Any app you actually paid for, you'll have to pay for again under the new ID. You shouldn't have to do anything with the native apps which were already installed on the iPad out of the box.