Add custom tab to Product Data area of Edit Product page - Add a custom field to Edit Product page. Add a custom tab to organise it. https://www.damiencarbery.com/2020/05/add-custom-tab-to-product-data-area-of-edit-product-page/

wc-tab-to-edit-product.php

<?php
/*
Plugin Name: Add custom tab to Product Data area of Edit Product page
Plugin URI: https://www.damiencarbery.com/2020/05/add-custom-tab-to-product-data-area-of-edit-product-page/
Description: Add a custom field to Edit Product page. Add a custom tab to organise it.
Author: Damien Carbery
Version: 0.1
*/


// Add a new 'Care Information' tab to Product Data area of Edit Product page.
add_filter( 'woocommerce_product_data_tabs', 'dcwd_care_instruction_product_data_tab' );
function dcwd_care_instruction_product_data_tab( $tabs ) {
	$tabs['where'] = array(
					'label'    => 'Care Information',
					'target'   => 'care_instruction_product_data',
					'priority' => 90,
				);
	return $tabs;
}
 
 
// Return an array of the options. This is used in multiple functions and
// is used to validate/sanitise the submitted value.
function dcwd_care_instructions() {
	$care_instructions = array(
		'cold'  => 'Wash at 30&deg;C',
		'warm'  => 'Wash at 40&deg;C',
		'hot'   => 'Wash at 60&deg;C',
	);
	return $care_instructions;
}
 
 
// Add the Delivery Option tab contents.
add_action( 'woocommerce_product_data_panels', 'care_instruction_data_panel', 100 );
function care_instruction_data_panel() {
?>
<div id="care_instruction_product_data" class="panel woocommerce_options_panel">
	<div class="options_group care_instruction">
<?php
    woocommerce_wp_radio( array(
        'id'            => '_care_instruction',
        'label'         => 'Care instruction',
        'options'       => dcwd_care_instructions(),
    ) );
?>
	</div>
</div>
<?php
}


// Save Care Information radio field to post meta.
// Save code is based on: https://businessbloomer.com/woocommerce-display-rrp-msrp-manufacturer-price/
add_action( 'save_post_product', 'dcwd_save_care_instruction' );
  function dcwd_save_care_instruction( $product_id ) {
    global $pagenow, $typenow;
    if ( 'post.php' !== $pagenow || 'product' !== $typenow ) return;
    if ( defined( 'DOING_AUTOSAVE' ) && DOING_AUTOSAVE ) return;

    if ( isset( $_POST['_care_instruction'] ) ) {
		if ( $_POST['_care_instruction'] ) {
			$care_instructions = dcwd_care_instructions();
			// Verify that the submitted value is a valid one.
			if ( array_key_exists( $_POST['_care_instruction'], $care_instructions ) ) {
				update_post_meta( $product_id, '_care_instruction', $_POST['_care_instruction'] );
			}
		}
    } else {
		delete_post_meta( $product_id, '_care_instruction' );
	}
}


// Add to the "Additional Information" tab on the single product page.
add_action( 'woocommerce_product_additional_information', 'dcwd_display_care_instruction', 10 ); 
function dcwd_display_care_instruction( $product ) {
    if ( 'variable' != $product->get_type() && $care_instruction = get_post_meta( $product->get_id(), '_care_instruction', true ) ) {
		$care_instructions = dcwd_care_instructions();
        printf( '<p>Care instruction: %s</p>', $care_instructions[ $care_instruction ] );
    }
}