SMTPDebug = 0; $mail->isSMTP(); $mail->Host = 'smtp.example.com'; $mail->SMTPAuth = true; $mail->Username = 'user@example.com'; $mail->Password = 'password'; $mail->SMTPSecure = 'tls'; $mail->Port = 587; $mail->setFrom('from@example.com', 'Sender Name'); $mail->addAddress('recipient@example.com'); $mail->addAttachment('/path/to/file.pdf'); $mail->isHTML(true); $mail->Subject = 'Test Email Subject'; $mail->Body = 'This is a test email message.'; $mail->send(); echo 'Message has been sent'; } catch (Exception $e) { echo "Message could not be sent. Mailer Error: {$mail->ErrorInfo}"; }This example uses PHPMailer to send an email with an attachment. The `addAttachment()` method is used to specify the file path of the attachment. The library automatically determines the encoding, content type, and transfer encoding. IsQmail, on the other hand, is a mail server that provides a faster and easier way to send emails over the Internet. It can be used with PHPMailer library to send emails from PHP applications. However, IsQmail is not a package library, but a software program available as an open-source tool. It can be integrated with various mail delivery libraries and email clients to send emails without configuring complex mail servers.