I want to reset my iPad but is the same Apple ID of my iPhone, what should I do?

If erasing a device for reuse by somebody else, the iPad needs to be properly prepared - after which the iPad can be set-up again “as new” by the new owner. The procedure to properly prepare the iPad completely erases the device - and, crucially, removes the Activation Lock that will otherwise cause difficulties.

The process that you need to follow is described here:

What to do before you sell, give away, or trade in your iPhone or iPad - Apple Support

Resetting your iPad will have absolutely no impact upon other devices that are signed-in with the same AppleID.

What, specifically, are you seeking to achieve in resetting your iPad?