You can use CapeChat UI to mess around with it: https://chat.capeprivacy.com/

Or you can also create a free API key here: https://app.capeprivacy.com/api-keys to use the interactive API directly: https://api.capeprivacy.com/v1/docs#/Privacy/DeidentifyText

Click "Authorize" on the top right to add the key, and then click "Try it out" on any of the endpoints.