How to report Missing device to local lae enforcement?

Theft needs to be reported direct the appropriate branch of law enforcement in your area. Apple will not be involved in this activity.

As for technical process, 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 the iPad have been lost.

You need to have had the Find My app enabled before it was stolen.

If you did not, there is nothing you can do. And yes, you can report it to the police.