Mail Chimp

Go To MailChimp for WP >> Insert MailChimp API Settings

Go To MailChimp for WP >> Form

Customize code like here:

<div class="ova-form-mail-chimp"><div class="name">  <input type="text" name="NAME" placeholder="Your name"  /></div><div class="email">  <input type="email" name="EMAIL" placeholder="Your email address" required /></div><div class="submit">  <input type="submit" value="Sign up!" /></div>
  <div class="hide">  <label>List choice</label><label>    <input name="_mc4wp_lists[]" type="checkbox" value="a328b7e698" checked="checked"> <span>VNTravelBooks</span></label>  </div></div>

Note: you have to change "above Bold Text" to your list choice