Now in OpenCart 3.0 and 2.3.0.1 version, it is very easy to setup google reCaptcha in multiple pages. Forms of Opencart that google reCaptcha supported are Register, Guest Checkout, Reviews, Returns, and Contact.
Basic Captcha:
Go to Extensions >> Extensions >> In Choose the extension type >> Captchas (2)
Now click the green button to install the Basic Captcha
Click the blue edit button of Basic Captcha
Choose Enabled from the status
Click save and you are set
Google reCaptcha:
Go to Extensions >> Extensions >> In Choose the extension type >> Captchas (2)
Now click the green button to install the Google reCaptcha
Click the blue edit button of Google reCaptcha
How to set it up in Google reCaptcha admin?
Go to https://www.google.com/recaptcha/admin (login with Gmail account if not) and enter your Label(Any name) and domain name(website URL). New style with reCAPTCHA v3: After entering the label select the reCAPTCHA type “reCAPTCHA v2” and then select “I’m not a robot” Checkbox” and in the Domain, enter your domains name
Old style:
When you click the register button, you will get the site key and secret key in the Keys tab. New style: Old style