Add a custom meta visual editor to the "Edit Term" page of a WooCommerce product_cat

functions.php

<?php

// Edit term page
add_action( 'product_cat_edit_form_fields', 'wpm_taxonomy_edit_meta_field', 10, 2 );

function wpm_taxonomy_edit_meta_field($term) {
 
  // put the term ID into a variable
  $t_id = $term->term_id;
 
  // retrieve the existing value(s) for this meta field. This returns an array
  $term_meta = get_option( "taxonomy_$t_id" );
  $content = $term_meta['custom_term_meta'] ? wp_kses_post( $term_meta['custom_term_meta'] ) : '';
  $settings = array( 'textarea_name' => 'term_meta[custom_term_meta]' );
  ?>
  <tr class="form-field">
  <th scope="row" valign="top"><label for="term_meta[custom_term_meta]"><?php _e( 'Details', 'wpm' ); ?></label></th>
    <td>
      <?php wp_editor( $content, 'product_cat_details', $settings ); ?>
      <p class="description"><?php _e( 'Detailed category info to appear below the product list','wpm' ); ?></p>
    </td>
  </tr>
<?php
}