WooCommerce Registration Custom Fields Saving

registration-form.php

<?php 

/** Save the extra register fields. */
function wooc_save_extra_register_fields( $customer_id ) {
	if ( isset( $_POST['billing_first_name'] ) ) {
		// WordPress default first name field.
		update_user_meta( $customer_id, 'first_name', sanitize_text_field( $_POST['billing_first_name'] ) );
		// WooCommerce billing first name.
		update_user_meta( $customer_id, 'billing_first_name', sanitize_text_field( $_POST['billing_first_name'] ) );
	}
	
	if ( isset( $_POST['billing_last_name'] ) ) {
		// WordPress default last name field.
		update_user_meta( $customer_id, 'last_name', sanitize_text_field( $_POST['billing_last_name'] ) );
		// WooCommerce billing last name.
		update_user_meta( $customer_id, 'billing_last_name', sanitize_text_field( $_POST['billing_last_name'] ) );
	}
	
	if ( isset( $_POST['billing_phone'] ) ) {
		update_user_meta( $customer_id, 'billing_phone', sanitize_text_field( $_POST['billing_phone'] ) );
	}
	
	if ( isset( $_POST['billing_company'] ) ) {
		update_user_meta( $customer_id, 'billing_company', sanitize_text_field( $_POST['billing_company'] ) );
	}
	
	if ( isset( $_POST['subscribe_to_newsletter'] ) ) {
		update_user_meta( $customer_id, 'subscribe_to_newsletter', sanitize_text_field( $_POST['subscribe_to_newsletter'] ) );
	}
}
add_action( 'woocommerce_created_customer', 'wooc_save_extra_register_fields' );

/** Assign user role */
function wooc_assign_user_role($customer_data){
    if ( isset( $_POST['user_role'] ) ) {
		$customer_data['role'] = sanitize_text_field($_POST['user_role']);
    }
    return $customer_data;
}
add_filter( 'woocommerce_new_customer_data', 'wooc_assign_user_role');

/** Set default display name */
function default_display_name($name) {
	if ( isset( $_POST['billing_first_name'] ) ) {
		$firstname = sanitize_text_field( $_POST['billing_first_name'] );
	}
	
	if ( isset( $_POST['billing_last_name'] ) ) {
		$lastname = sanitize_text_field( $_POST['billing_last_name'] );
	}
	$name = $firstname . ' ' . $lastname;
	
	return $name;
}
add_filter('pre_user_display_name','default_display_name');