Create register form without a plugin

Question

How can we create register form without using a plugin in wordpress theme development and how the form datas can be saved in database? since i am new to theme development, i have no idea..help me out!!!i have this simple register form and i dont know how to implement this in wordpress without using a plugin in my theme.i want to know how user registeration mechanism works in wordpress.

        <div class="col-md-6 login-do">
            <input type="hidden" name="action" value="add_foobar">
            <input type="hidden" name="data" value="foobarid">

            <div class="login-mail">
                <input type="text" placeholder="Name"  name='user_name' required="">
                <i  class="glyphicon glyphicon-user"></i>
            </div>
            <div class="login-mail">
                <input type="text" placeholder="Phone Number" name='user_number' required="">
                <i  class="glyphicon glyphicon-phone"></i>
            </div>
            <div class="login-mail">
                <input type="text" placeholder="Email" name='user_email' required="">
                <i  class="glyphicon glyphicon-envelope"></i>
            </div>
            <div class="login-mail">
                <input type="password" placeholder="Password" name='user_password' required="">
                <i class="glyphicon glyphicon-lock"></i>
            </div>
            <a class="news-letter " href="#">
                <label class="checkbox1"><input type="checkbox" name="checkbox" ><i> </i>Forget Password</label>
            </a>
            <label class="hvr-skew-backward">
                <input type="submit" value="Submit" name="submit">
            </label>
        </div>

Answer 1

In your PHP, use wp_create_user().

With this function, you can pass username, email and `password'.

Then, wp_update_user() to give the user the other bits of info.

I would hook my user-creation function to the init hook.

Also, you want to put a nonce field in your form e.g. this, between the <form> tags:

<?php wp_nonce_field( 'create_user_form_submit', 'djie3duhb3edub3u' ); ?>

E.g.

add_action('init', 'my_theme_create_new_user');
function my_theme_create_new_user(){

    if ( 
        ! isset( $_POST['djie3duhb3edub3u'] ) 
        || ! wp_verify_nonce( $_POST['djie3duhb3edub3u'], 'create_user_form_submit') 
    ){
       // do nothing
    }else{
        $username = sanitize_text_field($_POST['user_name']);
        $email = sanitize_text_field($_POST['user_email']);
        $password = $_POST['user_password'];
        $user_id = username_exists( $username );
        if ( !$user_id and email_exists($email) === false ) {
        
            // do some code to validate password how ever you want it.

            $user_id = wp_create_user( $username, $password, $email );
            $stuff = array('ID'=>$user_id,'another_user_field'=>'something');
            wp_update_user($stuff) // first name, last name etc
         } else {
             return false; //username exists already
         }
     }
}

• https://developer.wordpress.org/reference/functions/wp_create_user/
• https://developer.wordpress.org/reference/functions/wp_update_user/
• https://developer.wordpress.org/reference/functions/wp_nonce_field/