Install ReCaptcha to Umbraco V7

I would like to install ReCaptcha to our Umbraco Version 7. But I can’t seem to find the correct approach. Basically I want to add the captcha element inside my custom form (not the Umbraco Form). Is there a way to do it? It seems the approach of adding the Recaptcha is not the same as how you add it in PHP application. How should I do this in Umbraco?