How do i create a "Send Email" script using this code?

<form action=""method="post"> <div class="row"> <!-- Start Single Input --> <div class="col-md-12"> <div class="single-input"> <input type="text" name="nomeCompleto" placeholder="Nome Completo" required> </div> </div> <!-- End Single Input --> <!-- Start Single Input --> <div class="col-md-12"> <div class="single-input"> <input type="email" name="email" placeholder="E-Mail" required> </div> </div> <!-- End Single Input --> <!-- Start Single Input --> <div class="col-md-12"> <div class="single-input"> <input type="text" name="assunto" placeholder="Assunto" required> </div> </div> <!-- End Single Input --> <!-- Start Single Textarea --> <div class="col-md-12"> <div class="single-input"> <textarea name="mensagem" placeholder="Digite sua Mensagem" required></textarea> </div> </div> <!-- End Single Textarea --> <!-- Start Single Button MSG --> <div class="col-md-12"> <div class="button-MSG"> <a href="#" name="enviar" class="bttn-appnova-gradient">

<i class="fa fa-paper-plane"></i>

<span>Enviar</span>

</a> </div> </div> <!-- End Single Button MSG --> </div> </form>