Good day to you armstrong_738,
The following article goes over the process for turning on Lost Mode for AirPods (3rd generation), AirPods Pro and AirPods Pro (2nd generation), or AirPods Max. Find your lost AirPods With Lost Mode, you can share a message with your phone number or email address. If someone finds your AirPods, the message appears on their iPhone.
Turn on Lost Mode:
1. On your iPhone, iPad, or iPod touch, open the Find My app.
2. Go to the Devices tab, and choose your AirPods.
3. Scroll down to Mark as Lost, and select Activate.
4. Follow the onscreen steps if you want your contact information to display for your missing AirPods.
5. Select Activate.
Note: To mark your AirPods as lost, the Find My network must be on before AirPods are lost.
This next article also goes over what happens if you receive a message that an item or device, such as AirPods, are connected to another Apple ID when attempting to set them up. If an item or device is connected to another Apple ID. Though a device can be reset, it still won’t be able to be associated with a different Apple ID.
Lastly, to report a device as lost or stolen, you'd do that through your local law enforcement.
Thanks.