Add custom fields to variation in wooCommerce admin panel

Tested on php 7.4 wp 5.5.1 wooCommerce 4.5.2

The following code add a select box on each product variation

<?php
add_action( 'woocommerce_product_after_variable_attributes', 'variation_settings_fields', 10, 3 );

    function variation_settings_fields( $loop, $variation_data, $variation ) {

	// Select
	woocommerce_wp_select( 
	array( 
		'id'          => '_selectB2cB2b[' . $variation->ID . ']', 
		'label'       => __( 'Visible on', 'woocommerce' ), 
	
		'value'       => get_post_meta( $variation->ID, '_selectB2cB2b', true ),
		'options' => array(
			'both'   => __( 'Shop and business site', 'woocommerce' ),
			'onlyshop'   => __( 'Only on Shop', 'woocommerce' ),
			'onlybusiness' => __( 'Only on Business', 'woocommerce' )
			),
		'description' => __( 'Questa opzione limita la visualizzazione della variante a determinate tipologie di utente (business o shop)', 'woocommerce' ),
		'desc_tip'    => true	
		)
		);

    }

	add_action( 'woocommerce_save_product_variation', 'save_variation_settings_fields', 10, 2 );
	function save_variation_settings_fields( $variation_id, $loop ) {



		 $selectB2cB2b = $_POST['_selectB2cB2b'][ $variation_id ];


		If( isset($selectB2cB2b)){
		  update_post_meta( $variation_id, '_selectB2cB2b', esc_attr( $selectB2cB2b )); 
		  }

	}

It can be called on the product page by:
var_dump(get_post_meta( $available_variations[$key][‘variation_id’], ‘licence_ppl’, true ));

Note that in this case i’m in a foreach [foreach ($available_variations as $key => $value) ]

You can add the following type of custom fields

• Text Field
• Number Field
• Textarea
• Dropdown Select
• Checkbox
• Hidden field

For more informations, you can check this interesting article from Rémi Corson

Questions? Suggestions? Please leave a comment below.
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