从bulma表单获取信息

I am new to bulma css framework and have implemented the following code for an input text box and submit button

<div class="box">
  <div class="field is-grouped">
    <p class="control is-expanded">
      <input class="input" type="text" placeholder="Enter your email">
    </p>
    <p class="control">
      <a class="button is-info">
        Get in Touch
      </a>
    </p>
  </div>
</div>

Now I am unable to understand that how do I write the php code with it, I have seen in various tutorials that the form tag uses php script, but on case of bulma wherein i have a box class, how do I integrate php to it