How old is this iPad?
Apple Store locations, for the most, do NOT repair iPads.
To expedite quick and speedy customer service, Apple stores only do in/out-of-warranty device replacement.
For battery service, iPad replacement is done in lieu of an actual, physical teardown in order to perform an actual battery replacement.
Depending on the age of your iPad such a device replacement Apple Store locations may, or may not, be able to offer a replacement iPad, of your exact model, for the battery replacement service.
Not sure what Apple Store locations do when there is no replacement device inventory for a particular Apple mobile device model.
Battery replacement for iPads is $99 U.S.D., plus tax.
So, depending on how old this iPad is, a $99 U.S.D. battery replacement cost may not be practical.
Especially for any Apple mobile device that may no longer be supported by Apple and is consideted a vintage or obsolete device.
You need to use the “Get Support” link, in the top black menu bar, at the upper right hand corner of every Apple Support Community Webpage to attempt to schedule an appointment with your nearest Apple Store location to schedule a battery diagnisis and replacement for that iPad
Apple Store employees will be glad to help/assist you.
Best of Luck to You!