How can case sensitivity in PHP variables impact the functionality of extracting and using form data, such as the email address, for email headers?

Case sensitivity in PHP variables can impact the functionality of extracting and using form data for email headers because if the variable names are not consistent, the data may not be correctly retrieved or used. To solve this issue, ensure that the variable names used to extract form data match the case sensitivity of the form input names. This will ensure that the data is correctly retrieved and used in constructing email headers.

$email = $_POST['email']; // Ensure that the form input name is 'email' and not 'Email' or 'EMAIL'
$headers = "From: $email"; // Use the correct variable name to include the email address in the email headers
// Additional code to send the email using the $headers variable