<form action="https://fabform.io/f/xxxxx" method="post">
  <label for="firstName">First Name</label>
  <input name="firstName" type="text" required>
  <label for="lastName">Last Name</label>
  <input name="lastName" type="text" required>
  <label for="email">Email</label>
  <input name="email" type="email" required>
  <label for="files">Choose files:</label>
  <input type="file" name="files" multiple required />
  <button type="submit">Send</button>
</form>