PHP:
<form class="w-full flex-w flex-c-m validate-form">
<div class="wrap-input100 validate-input m-b-20" data-validate = "Valid email is required:manager.mc@outlook.it">
<input class="input100 placeholder0 m1-txt1" type="text" name="email" placeholder="Email Address">
<span class="focus-input100"></span>
</div>
<button class="flex-c-m size3 m1-txt2 how-btn1 trans-04 m-b-20">
Iscriviti
</button>
</form>