woocommerce_save_custom_fields.php

<?php
// Save All Fields
add_action( 'woocommerce_process_product_meta', 'ci_custom_general_tab_fields_save' );

//Saving Fields Values
function ci_custom_general_tab_fields_save( $post_id ){
	
	// Text Field
	$woocommerce_text_field = $_POST['_text_field'];
	if( !empty( $woocommerce_text_field ) )
		update_post_meta( $post_id, '_text_field', esc_attr( $woocommerce_text_field ) );
		
	// Number Field
	$woocommerce_number_field = $_POST['_number_field'];
	if( !empty( $woocommerce_number_field ) )
		update_post_meta( $post_id, '_number_field', esc_attr( $woocommerce_number_field ) );
		
	// Textarea
	$woocommerce_textarea = $_POST['_textarea'];
	if( !empty( $woocommerce_textarea ) )
		update_post_meta( $post_id, '_textarea', esc_html( $woocommerce_textarea ) );
		
	// Select
	$woocommerce_select = $_POST['_select'];
	if( !empty( $woocommerce_select ) )
		update_post_meta( $post_id, '_select', esc_attr( $woocommerce_select ) );
		
	// Checkbox
	$woocommerce_checkbox = isset( $_POST['_checkbox'] ) ? 'yes' : 'no';
	update_post_meta( $post_id, '_checkbox', $woocommerce_checkbox );
	
	// Custom Field One
	$custom_field_one =   esc_attr( $_POST['_field_one'] );
	update_post_meta( $post_id, '_custom_field_one', $custom_field_one );
    
    
   	// Custom Field Two
	$custom_field_two =   esc_attr( $_POST['_field_two'] );
	update_post_meta( $post_id, '_custom_field_two', $custom_field_two );
    
	
	// Hidden Field
	$woocommerce_hidden_field = $_POST['_hidden_field'];
	if( !empty( $woocommerce_hidden_field ) )
		update_post_meta( $post_id, '_hidden_field', esc_attr( $woocommerce_hidden_field ) );
		
	// Product Field Type
	$product_field_type =  $_POST['product_field_type'];
	update_post_meta( $post_id, '_product_field_type_ids', $product_field_type );
	
}