hCaptcha is a captcha service provider which is similar to reCAPTCHA. You can see more details from this link.
Create an API key pair
Then you can get a site key and a secret key.
Configure in Casdoor
Create a new provider in Casdoor.
Select category as Captcha , type as hCaptcha . And you need to fulfill the site key and the secret key which is created by last step.
And you can click Preview botton to preview the style of this captcha.
Applied in application
Edit the application you want to configure in Casdoor. Select the provider just added and click the button Save.