How can one prevent emails from a website being marked as junk mail?

To prevent emails from a website being marked as junk mail, you can ensure that the email content is relevant and engaging, use a recognizable sender name and email address, avoid using spam trigger words in the subject line and body of the email, and regularly clean your email list to remove inactive or invalid addresses.

// Example PHP code to prevent emails from being marked as junk mail
$to = "recipient@example.com";
$subject = "Important message from Your Website";
$message = "Hello, this is a message from Your Website. Please let us know if you have any questions.";
$headers = "From: Your Website <noreply@yourwebsite.com>\r\n";
$headers .= "Reply-To: noreply@yourwebsite.com\r\n";
$headers .= "Content-Type: text/html; charset=UTF-8\r\n";

// Send the email
mail($to, $subject, $message, $headers);