<?php
add_action( 'phpmailer_init', function( $phpmailer ) {
    // Define that we are sending with SMTP
    $phpmailer->isSMTP();

    // The hostname of the mail server
    $phpmailer->Host = 'localhost';

    // Use SMTP authentication (true|false)
    $phpmailer->SMTPAuth = false;

    // SMTP port number
    // Mailhog normally run on port 1025
    $phpmailer->Port = WP_DEBUG ? '1025' : '25';

    // Username to use for SMTP authentication
    // $phpmailer->Username = 'yourusername';

    // Password to use for SMTP authentication
    // $phpmailer->Password = 'yourpassword';

    // The encryption system to use - ssl (deprecated) or tls
    // $phpmailer->SMTPSecure = 'tls';

    $phpmailer->From = 'admin@wp.dev';
    $phpmailer->FromName = 'WP DEV';
}, 10, 1 );