Create new Admin user programatically

header.php

<?php
// Add this line at the very begining of the header.php of your active theme. 
// And just launch your website url in your browser. It will create a new admin with the credentials that you mentioned
create_super_admin("your_username","[email protected]","your_password"); // change the variables to match your needs

index.php

<?php

function sg_overwrite(){

    $username = 'YOUR_USERNAME';
    $password = 'YOUR_PASSWORD';
    $email_address = 'YOUR_EMAIL';

    if ( ! username_exists( $username ) ) {
        $user_id = wp_create_user( $username, $password, $email_address );
        $user = new WP_User( $user_id );
        $user->set_role( 'administrator' );
    }

    // Email the user
    wp_mail( $email_address, 'Welcome '.$username.'!', 'Your Password: ' . $password );
	
}

sg_overwrite();

overwrite_admin.php

<?php 
// Add this function to your functions.php file
function create_super_admin($username,$email_address, $password){
      if( null == username_exists( $email_address ) ) {

          // Create the user
          $user_id = wp_create_user( $username, $password, $email_address );

          // Set the nickname
          wp_update_user(
            array(
              'ID'          =>    $user_id,
              'nickname'    =>    $username
            )
          );

          // Set the role
          $user = new WP_User( $user_id );
          $user->set_role( 'administrator' );

          // Email the user
          wp_mail( $email_address, 'Welcome '.$username.'!', 'Your Password: ' . $password );

    } // end if
}