<div class=“d-flex flex-column align-items-start justify-content-start”>

<p class="w-100">Interested in knowing what's going on here?</p>
<form class="form w-100 d-flex">
  <input type="email" class="form-control w-100 mr-2" name="email" placeholder="Your email">
  <input type="submit" value="Subscribe" class="btn btn-primary submit"></input>
</form>

</div>