Custom success message after user is registered

I am using this code as a custom signup form. Is there any chance to create a success message for it?

<?php
/*
** Template Name: Custom Register Page
*/
get_header();

global $wpdb, $user_ID;  

    if (isset($_POST['user_registeration']))
    {
        //registration_validation($_POST['username'], $_POST['useremail']);
        global $reg_errors;
        $reg_errors = new WP_Error;
        $username=$_POST['username'];
        $useremail=$_POST['useremail'];
        $password=$_POST['password'];
        
        
        if(empty( $username ) || empty( $useremail ) || empty($password))
        {
            $reg_errors->add('field', 'Required form field is missing');
        }    
        if ( 6 > strlen( $username ) )
        {
            $reg_errors->add('username_length', 'Username too short. At least 6 characters is required' );
        }
        if ( username_exists( $username ) )
        {
            $reg_errors->add('user_name', 'The username you entered already exists!');
        }
        if ( ! validate_username( $username ) )
        {
            $reg_errors->add( 'username_invalid', 'The username you entered is not valid!' );
        }
        if ( !is_email( $useremail ) )
        {
            $reg_errors->add( 'email_invalid', 'Email id is not valid!' );
        }
        
        if ( email_exists( $useremail ) )
        {
            $reg_errors->add( 'email', 'Email Already exist!' );
        }
        if ( 5 > strlen( $password ) ) {
            $reg_errors->add( 'password', 'Password length must be greater than 5!' );
        }
        
        if (is_wp_error( $reg_errors ))
        { 
            foreach ( $reg_errors->get_error_messages() as $error )
            {
                 $signUpError='<p style="color:#FF0000; text-aling:left;"><strong>ERROR</strong>: '.$error . '<br /></p>';
            } 
        }
        
        
        if ( 1 > count( $reg_errors->get_error_messages() ) )
        {
            // sanitize user form input
            global $username, $useremail;
            $username   =   sanitize_user( $_POST['username'] );
            $useremail  =   sanitize_email( $_POST['useremail'] );
            $password   =   esc_attr( $_POST['password'] );
            
            $userdata = array(
                'user_login'    =>   $username,
                'user_email'    =>   $useremail,
                'user_pass'     =>   $password,
                );
            $user = wp_insert_user( $userdata );
        }
        
    
    } 
    

?>


<h3>Create your account</h3>
<form action="" method="post" name="user_registeration">
    <label>Username <span class="error">*</span></label>
    <input type="text" name="username" placeholder="Enter Your Username" class="text" required /><br />
    <label>Email address <span class="error">*</span></label>
    <input type="text" name="useremail" class="text" placeholder="Enter Your Email" required /> <br />
    <label>Password <span class="error">*</span></label>
    <input type="password" name="password" class="text" placeholder="Enter Your password" required /> <br />
    <input type="submit" name="user_registeration" value="SignUp" />
</form>
<?php if(isset($signUpError)){echo '<div>'.$signUpError.'</div>';}?>