How can I group form fields using semantic structure?

<!-- BEGIN COPY / PASTE -->
    <form>
      <fieldset>
        <legend>Personal Information</legend>
        <label for="name">Name:</label>
        <input type="text" id="name" name="name">
        
        <label for="email">Email:</label>
        <input type="email" id="email" name="email">
      </fieldset>
      
      <fieldset>
        <legend>Account Details</legend>
        <label for="username">Username:</label>
        <input type="text" id="username" name="username">
        
        <label for="password">Password:</label>
        <input type="password" id="password" name="password">
      </fieldset>
    </form>
    <!-- END COPY / PASTE -->