To add Google reCAPTCHA v2 to a form, you will first need to integrate your Google account with your website. For this, open a form that you would like to integrate with Google reCAPTCHA v2. At the bottom of the form, add the CAPTCHA field, which you can find under Advanced Fields and save the form.
The CAPTCHA field will instruct you to sign up with Google for an API key pair for your site. Click on the Sign Up link to go to Google reCAPTCHA page.
While registering your site on this page, select Google reCAPTCHA v2 and then choose ‘I’m not a Robot’ option.
Google will provide you with a Site Key and a Secret Key which you will have to copy to your form.
Go back to your WordPress dashboard and click on Forms > Settings. Then select reCAPTCHA. Under reCAPTCHA Settings, there are reCAPTCHA V3 and reCAPTCHA v2 sections. Be sure to paste the keys under reCAPTCHA V2 section.
Select Checkbox type. If you opted for Invisible instead of Checkbox in Google settings previously, select that and click on Save Settings.
Now switch back to your form – click Update to save what you have already created and to refresh the page. Now reCAPTCHA v2 should work in your form.