My iPad is stolen

This document has a list of things to do if your iPhone, iPad, or iPod touch is lost or stolen. --> If your iPhone, iPad, or iPod touch is lost or stolen - Apple Support

Some of the things you can do by logging into iCloud.com

Hello yaser174,

I can understand how stressful getting you iPad stolen can be. You have asked how to lock the iPad without using Find My. That is impossible. I recommend login to the Apple ID in question and locking it in Find My. I have a YouTube Video and a link to a Apple Support Article below.

If your iPhone, iPad or iPod touch is lost or stolen – Apple Support (UK)

Hopefully you will be able to get your iPad back! My wishes are with you.

Paramveer