<form class="needs-validation stepper-form w-100" method="post"

      action="register.php"

      enctype="multipart/form-data">

    <ul class="stepper stepper-horizontal" id="user-registration-stepper" data-mdb-stepper-linear="true"

        data-mdb-stepper-mobile-breakpoint="450">

<!-- First step -->

        <li class="stepper-step stepper-active">

            <div class="stepper-head" tabindex="0">

                <span class="stepper-head-icon"> 1 </span>

                <span class="stepper-head-text"> First </span>

            </div>

            <div class="stepper-content py-3">aaaa

                         </div>

        </li>

        <!-- First step -->

​

        <!-- Second step -->

        <li class="stepper-step" data-mdb-stepper-optional="true">

            <div class="stepper-head">

                <span class="stepper-head-icon"> 2 </span>

                <span class="stepper-head-text">Second</span>

            </div>

          <div class="stepper-content py-3" style="display: none;">

          bbbb</div>

      </li>

  </ul>

</form>