What are the consequences of not using correct HTML tags in PHP form elements, and how can this impact functionality?

Not using correct HTML tags in PHP form elements can impact functionality by causing errors in rendering the form or processing the input data. To ensure proper functionality, always use the correct HTML tags for form elements such as input, select, textarea, etc.

<form action="process_form.php" method="post">
    <label for="username">Username:</label>
    <input type="text" id="username" name="username">
    
    <label for="password">Password:</label>
    <input type="password" id="password" name="password">
    
    <input type="submit" value="Submit">
</form>