Gravity forms is one of the most most popular WordPress form plugins. Adding reCAPTCHA is pretty easy. Really Simple Captcha is one plugin that I've used that has a very streamline design. Here's how to set it up.
- Upload WP Plugin - Really Simple Captcha
- In Gravity forms follow link to create reCAPTCHA and set up website reCAPTCHA with Google. You’ll need to add the site key and secret key to Gravity forms settings.
3. You’ll need to add the site key and secret key to Gravity forms settings.
4. Select which ReCaptcha you want to use.
5. Another way to use reCaptcha is to add it to your WP login page to ward of bots from brute force login hacks.