how to use html tags in code behind to insert data in database in c#

Question

<form action="#" method="post" class="subscribe_form">
             <input id="TxtEmail" runat="server" class="form-control" type="text" placeholder="Enter your email..." required="">
            <button id="BtnEmail" runat="server" type="submit" class="btn btn-primary submit" >Submit</button>

</form>