Please visit https://www.google.com/recaptcha/ and look at the top right corner, click the Get reCAPTCHA link, and scroll down to Register a new site:

• Choose the type of reCAPTCHA: reCAPTCHA V3
• Enter your domain in the Domains setting.
• Finally, tick Accept the reCAPTCHA Terms of Service and click the Register button
• Once you have clicked on the Register button, Google will generate two keys: Site Key and Secret Key. Now log into your Nema Admin CP configuration page and use the keys.