Stolen iPad
Your iPad cannot be traced or remotely managed using the device Serial Number. For future reference, here is Apple’s advice for lost or stolen devices:
Locate a device in Find My on iPad - Apple Support
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 still active, you would stand a good chance of locating it. However, if the feature was not activated prior to being misplaced, has since been deactivated, or has been inactive and without a network connection for more than 24 hours, the last known location will not be available - and the opportunity to use technical means to recover the iPad have been lost.
Assuming that you still have access to your AppleID account (now also known as your Apple Account), you would be best advised to change your account Password:
Change your Apple Account password - Apple Support
If your iPad was a WiFi+Cellular model, with an active Cellular plan, ensure that you inform your Cellular Service Provider so that your plan can be suspended/cancelled and your IMEI blocked.
Advice
As described, either your iPad was not locked with a Passcode, or the Passcode was known to whoever stole the iPad. Unfortunately, for some inexplicable reason, iPadOS for iPad does not benefit from the Stolen Device Protection feature found in recent versions of iOS for iPhone. Stolen Device Protection for iPhone provides an additional layer of security that inhibits access to key areas of device settings.
About Stolen Device Protection for iPhone - Apple Support
While the Stolen Device Protection feature is not available for iPad, there are steps that you can employ that will make an iPad's settings considerably more difficult to compromise if stolen...
1) In addition to setting a complex device Passcode (that is known only to you), ensure that you have set (and actively use) either FaceID or TouchID.
Always use biometric FaceID or TouchID authentication whenever possible. Ensure that you never use your device Passcode in public, or anywhere that you might be observed by others - this being essential in protecting your Passcode from discovery through observing you!
Set up Face ID on iPad - Apple Support
Set up Touch ID on iPad - Apple Support
2) Set your ScreenTime Passcode - ensuring that this differs from the device Passcode used to unlock your iPad.
When setting the ScreenTime Passcode, you will be prompted to set a recovery email address or telephone number. Do not use the email address that identifies your AppleID, or any other email address that is configured for use on your iPad - as these will be potentially accessible to someone that has access to your iPad. Better still, when prompted for a recovery email address or phone number, skip this entirely (selecting Cancel, then Skip when prompted) - but be sure to remember whatever ScreenTime Passcode that you select - as without a recovery email address or phone number, this passcode cannot be reset or recovered:
Settings > ScreenTime > Lock ScreenTime Settings
3) Set three key ScreenTime restrictions for your iPad:
Settings > ScreenTime > [Restrictions] Content & Privacy Restrictions > [Allow Changes To] >
- Passcode & FaceID | TouchID - set to Don't Allow
- Accounts - set to Don't Allow
- Mobile Data - set to Don't Allow
Once you have set these restrictions, you (or anyone else) will not be able to change key settings without first removing the corresponding restriction using the ScreenTime Passcode - this being intentionally different to the unlock Passcode that provides access to both your iPad and all of your saved Passwords.
4) Critical: Never, ever, store your AppleID Account Password in your iPad's saved Passwords. This Password is something that you really must commit to memory. Ensure that your chosen Password is complex (perhaps choose three consecutive unrelated words that you will easily remember, but nobody else will guess).
Prior to iPadOS 18, any Passwords saved in your iPad settings can be simply accessed by anyone that has knowledge of your iPad device Passcode. With knowledge of both your device Passcode - and with it your AppleID Password (and other saved account passwords) - you can lose access to everything. Be mindful of saved banking or other significant account credentials - as a financial fraud is commonplace.