What considerations should be made for users who have HTML disabled in their email clients when sending HTML emails through PHP?

When sending HTML emails through PHP, it's important to consider users who have HTML disabled in their email clients. To ensure these users can still read the email content, you can include a plain text version of the email as well. This way, if the HTML version is not displayed properly, the recipient can still access the information in plain text format.

// Set the email headers
$headers = "MIME-Version: 1.0" . "\r\n";
$headers .= "Content-type:text/plain;charset=UTF-8" . "\r\n";

// Create the plain text version of the email
$plain_text = "Hello, this is the plain text version of the email.";

// Send the email with both HTML and plain text versions
mail($to, $subject, $html_content, $headers);