Reference link click here.
Using below code you can send the mail with html format.
$to = '[email protected]';
$subject="The subject";
$body = 'The email body content';
$headers = array('Content-Type: text/html; charset=UTF-8');
wp_mail( $to, $subject, $body, $headers );
// For attachment
$attachments = array( WP_CONTENT_DIR . '/uploads/file_to_attach.zip' );
$headers="From: My Name <[email protected]>" . "\r\n";
wp_mail( '[email protected]', 'subject', 'message', $headers, $attachments );