The HTML on the left is interactive, you can change the elements are included and the form to the right will be updated immediately. You can change your@email.com with your actual email address and then submit the form on the right to get the submission to your mailbox.
<div class="container">
<h1>JustSignup Demo</h1>
<form target="_blank" action="https://justsignup.com/your@email.com" method="POST">
<div class="form-group">
<div class="form-row">
<div class="col">
<input type="text" name="name" class="form-control" placeholder="Full Name" required>
</div>
<div class="col">
<input type="email" name="email" class="form-control" placeholder="Email Address" required>
</div>
</div>
</div>
<div class="form-group">
<textarea placeholder="Your Message" class="form-control" name="message" rows="10" required></textarea>
</div>
<button type="submit" class="btn btn-lg btn-dark btn-block">Submit Form</button>
</form>
</div>
Use this service to generate a temporary email address that you can use for testing: https://mail.tm/