Envoi de mail Formulaire avec php

<div class="container-contact100">
  <div class="wrap-contact100">
   <form class="contact100-form validate-form">
   <!--------------------TITRE-->
    <span class="contact100-form-title">
     <STRONG>DEMANDEZ VOTRE DEVIS</STRONG>
     <h5><font color="orange">
     Merci de remplir correctement ce formulaire!
     </font></h5>
    </span>


    <!--------------------Nom-->
    <div class="wrap-input100 validate-input" data-validate="Champ requis">
     <label class="label-input100" for="name">Nom</label>
     <input id="Nom" class="input100" type="text" name="Nom" placeholder="Nom">
     <span class="focus-input100"></span>
    </div>
    
    <!--------------------CATEGORIE-->
    <div class="wrap-input100">
     <div class="label-input100">Catégorie</div>
     <div>
      <select class="js-select2" name="Categorie">
       <option value="0">Définissez</option>
       <option value="Startup">Startup</option>
       <option value="PME/PMI">PME/PMI</option>
       <option value="Grande Entreprise">Grande Entreprise</option>
       <option value="Autre">Autre</option>    
      </select>
      <div class="dropDownSelect2"></div>
     </div>
     <span class="focus-input100"></span>
    </div>
    
    <!--------------------EMAIL-->
    <div class="wrap-input100 validate-input" data-validate = "Champ requis: e@an.c">
     <label class="label-input100" for="email">Adresse Email</label>
     <input id="Email" class="input100" type="text" name="Email" placeholder="Votre Email">
     <span class="focus-input100"></span>
    </div>
    
    <!--------------------CONTACT-->
    <div class="wrap-input100 validate-input" data-validate="Champ requis">
     <label class="label-input100" for="name">Contact</label>
     <input id="Contact" class="input100" type="number" name="Contact" placeholder="+0123456789">
     <span class="focus-input100"></span>
    </div>

    <!--------------------MESSAGE-->
    <div class="wrap-input100 validate-input" data-validate = "Champ requis">
     <label class="label-input100" for="message">Message</label>
     <textarea id="Message" class="input100" name="Message" placeholder="Décrivez Brièvement Votre Besoin..."></textarea>
     <span class="focus-input100"></span>
    </div>

    <!--------------------ENVOI-->
    <div class="container-contact100-form-btn">
     <button class="contact100-form-btn">
      Validez
     </button>
    </div>

   </form>

   <div class="contact100-more flex-col-c-m" style="background-image: url('images/bg-03.jpg');">
   </div>
  </div>
 </div>


 <script>
  $(".js-select2").each(function(){
   $(this).select2({
    minimumResultsForSearch: 20,
    dropdownParent: $(this).next('.dropDownSelect2')
   });
  })
  $(".js-select2").each(function(){
   $(this).on('select2:open', function (e){
    $(this).parent().next().addClass('eff-focus-selection');
   });
  });
  $(".js-select2").each(function(){
   $(this).on('select2:close', function (e){
    $(this).parent().next().removeClass('eff-focus-selection');
   });
  });

 </script>
<!--===============================================================================================-->