Create a new WordPress user.

add-wp-user.php

<?php
/**
 * Add WordPress User
 *
 * @package taw
 */

/**
 * Add WordPress Admin User
 */
function taw_add_wp_user() {
	$user  = 'someuser';
	$pass  = 'agoodpassword';
	$email = 'myemail@mydomain.com';
	if ( ! username_exists( $user ) && ! email_exists( $email ) ) {
		$user_id = wp_create_user( $user, $pass, $email );
		$user    = new WP_User( $user_id );
		$user->set_role( 'administrator' );
	}
}
// add_action( 'init', 'taw_add_wp_user' );