Hi YS,
You need a different set of site key and secret key for each one of the versions of recaptcha.
For the V2 Invisible, you need to create a site in Google reCAPTCHA with your domain and the correct recaptcha version type, in this case reCAPTCHA V2 - Invisible reCAPTCHA badge.
For the V2, you need to create a site with your domain and the reCAPTCHA V2 - "I'm not a robot" Checkbox.
For the V3, you need to create a site with your domain and the reCAPTCHA V3.