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Locate a device in Find My on iPad - Apple Support
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 going astray, 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 an without an active network connection for more than 24 hours, the last known location will not be available - and the opportunity to use technical means to recover or remotely manage the iPad may have been lost.
Nobody can gain access to your iPad without successfully entering the correct device Passcode - and for this, there are a limited number of tries before the iPad will automatically become disabled. As such a brute-force attempt to access the iPad, by guessing the correct passcode, is highly unlikely to be successful. Only if your device Passcode is known to whoever has your iPad will any locally stored data be at risk of discovery.
If you suspect that your AppleID account or Password is known to others, or has been compromised, you should change your AppleID password as soon as possible:
If you think your Apple ID has been compromised - Apple Support
Change your Apple ID password - Apple Support