The Find Hub app offers a "Lost Mode", which you can enable when you have lost your item and you want to share your contact information and a message with whoever finds it in order to have it returned to you.
Enabling "Lost Mode"
In addition to being notified when your item was spotted by another Google's Find Hub network enabled device, you can also set a message that would be shown to the person who finds your item with your phone number and email. You do this by enabling "Lost mode".
Tap on your Chipolo in the Find Hub app.
Tap on "Mark as lost".
On the screen that opens you have the option to enter a message for whoever finds it and to add a phone number and an email on which you can be reached.
Confirm enabling "Lost mode" by taping on the "Mark as lost" button at the bottom.