Does php mail function use imap or smtp by default

The PHP mail() function does not use IMAP or SMTP by default. Instead, it uses the mail transfer agent (MTA) configured on the server where the PHP script is running.

On most Linux systems, the default MTA is Sendmail or Postfix. On Windows systems, the default MTA is usually the Windows SMTP service.

When you use the mail() function in PHP, it sends the email to the MTA, which then delivers the email to the recipient's email server using the configured mail relay or directly to the recipient's email server if the recipient's email server is configured to accept mail directly.

If you want to use IMAP or SMTP explicitly in PHP, you would need to use a library such as PHPMailer or SwiftMailer, which provide more control over the email sending process and allow you to specify the IMAP or SMTP server settings.

Here's an example of how you might use PHPMailer to send an email using SMTP:

require 'PHPMailerAutoload.php';

$mail = new PHPMailer;

$mail->isSMTP();
$mail->Host = 'smtp.example.com';
$mail->SMTPAuth = true;
$mail->Username = 'your_email_address';
$mail->Password = 'your_email_password';
$mail->SMTPSecure = 'tls';
$mail->Port = 587;

$mail->setFrom('your_email_address', 'Your Name');
$mail->addAddress('recipient_email_address');
$mail->Subject = 'Test email';
$mail->Body = 'This is a test email';

if (!$mail->send()) {
    echo 'Error sending email: '. $mail->ErrorInfo;
} else {
    echo 'Email sent successfully!';
}

In this example, PHPMailer is configured to use the SMTP server at smtp.example.com to send the email. You would need to replace the placeholders with your own email address, password, and recipient's email address.