Here is Apple’s advice for lost or stolen devices:
If your iPhone, iPad or iPod touch is lost or stolen – Apple Support
Use the Find My app to locate a lost or stolen device – Apple Support
If the Find My iPad feature was enabled prior to it being “misplaced”, then if active, you would stand a good chance of locating it.
However, if the feature was not activated prior to being misplaced - or the iPad has been inactive for more than 24 hours, the last known location will not be available - and the opportunity to use technical means to recover or manage the iPad have been lost.
If you device is protected by a strong Passcode, unless the Passcode is known to whoever finds the device, your data will remain secure. The iPad has an encrypted filesystem - and without the correct passcode your data will forever remain beyond reach. After a limited number of failed attempts to enter the correct Passcode, the iPad will be disabled - this automatically erasing all cryptographic keys from the iPad.
If you had disabled Find My iPad, the Activation lock that inhibits re-use of the iPad was also disabled - however, your locally stored data will have been crypto-erased.