Step 1 : In the first step, we need to prepare API key for your site/domain where you want to implement Google recaptcha “I'm not aRobot”.
Go to link (https://www.google.com/recaptcha/admin)for create API key and see below instruction. i.e.
Step 2 : In the second step, get site key and secret key for display Google recaptcha. i.e.
Step 3 : Please use the api.js and data-sitekey for recaptcha. i.e.
JavaScript API URL code
<script src='https://www.google.com/recaptcha/api.js'></script>
HTML code
<div class="g-recaptcha" data-sitekey="6Ldbdg0TAAAAAI7KAf72Q6uagbWzWecTeBWmrCpJ"></div>
Step 4 : The example in detail about Google Recaptcha, How to use the “I'm not a Robot”? as given below.
<!DOCTYPE html>
<html lang="en">
<head>
<title>Google Recaptcha, How to use the “I'm not a Robot”</title>
<script src='https://www.google.com/recaptcha/api.js'></script>
</head>
<body>
<form action="" method="post">
<h1>Google Recaptcha, How to use the “I'm not a Robot”</h1>
<div>
<label for="name">Name:</label>
<input name="name" required>
</div>
<div>
<label for="email">Email:</label>
<input name="email" type="email" required><br />
</div>
<div>
<label for="phone">Phone:</label>
<input name="phone" type="phone" required><br />
</div>
<div class="g-recaptcha" data-sitekey="6Ldbdg0TAAAAAI7KAf72Q6uagbWzWecTeBWmrCpJ"></div>
<input type="submit" value="Submit" class="fb9" />
</form>
</body>
</html>
The live output,