Since Divi update 4.0.7 it is possible to natively integrate Google ReCaptcha v3 right into your contact form settings with only a few simple steps.
1. Create a google recaptcha profile for your site here — google.com/recaptcha/admin/create
2. After creating the above profile and click the Submit button you will see a recaptcha SITE KEY and SECRET KEY. Leave this window open as you’ll need the two keys at the ready.
3. Now enable the Divi builder on your site, edit your Contact Form module to include “Use a Spam Protection Service” under the Spam Protection option. You can copy and paste in your two keys from the previous step. That’s it! I went one step further for my own site and adjusted the “Minimum Score” to 0.7.