You can add a newsletter subscription form for collect email of your user, for sending promotional newsletter to them.

After installing all required plugins(MailChimp for WordPress) you will get a menu named MailChimp for WP navigate to that menu and add your mail chimp API(you need to have an account on mailchimp)

From submenu Form you can make a form for collect mail address from your users.

Copy and past this code in your form for make the same subscription form as our demo.

<div class="widget-subscription"> <span class="sub-title">SUBSCRIBE US</span> <h3>Get Even More</h3> <p class="note">"Get all latest content delivered straight to your inbox."</p> <div class="form-group"> <input id="subscribeEmail" type="email" class="form-control" name="EMAIL" placeholder="email@address.com" required /> </div> <input value="YES! LET’S DO THIS" type="submit"> <!-- to showing success messages --> <p class="subscription-info">We never spam you</p> <p class="subscription-success"></p> </div>