How can I track my lost iPad if Find My is off?

Start here:

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 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 or 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.

If Find My was not activated on the iPad before it was lost, then you are not going to be able to activate it. The only way to find your iPad now is by looking for it the old fashioned way. Search for it physically. If you suspect that it was stolen, then report the incident to the local police.

Axel F.