Hey there wellic,
We understand you have a question about changing your Apple ID and a stolen iPad, and we'd like to share a resource that can help.
Changing your Apple ID password won't remove the Activation Lock on the device. Learn more about what to do here: If your iPhone, iPad, or iPod touch is lost or stolen
Specifically, take a look at this note:
"Find My [device] is the only way that you can track or locate a lost or missing device. If Find My [device] isn't enabled on your device before it goes missing, there's no other Apple service that can find, track, or flag your device for you."
Cheers!