Ideally your iPad will be properly prepared prior to sending for repair:
What to do before you sell, give away, or trade in your iPhone or iPad - Apple Support
In following the documented process, your iPad will:
a) not be associated with your AppleID
b) have had Find My (and the associated Activation Lock) disabled
c) have been fully erased
As such, when presented for repair, the device has no technical association to you. If you are seeking a warranty repair, whoever presents the device will need to provide appropriate proof of warranty entitlement - this typically being the original sales invoice. If warranty repair is not being sought, contact details for whoever is contracting the repair, along with an appropriate payment method, will be needed. The person requesting service may be asked for valid proof of identity.
If your device is inoperable, you'll clearly not be able to fully erase and disable the Activation Lock - and in such circumstances the owner of the AppleID to which the Activation Lock relates will need to be present. Clearly, nobody should "share" their AppleID account credentials with anyone else - and contributors here would never "suggest" that you to do so - and as such someone with knowledge of the account credential would be reasonably assumed to be the owner of the account.
Get your iPhone, iPad, or iPod touch ready for service - Apple Support