custom-html-cat-id.php

public function add_custom_html() {
            global $post;
            $product_id = $post->ID; 
            $categories = get_the_terms( $product_id, 'product_cat' );

            if( empty ($categories)){
                return;
            }

            $content = "
                    <table>
                        <tr>
                            <th></th>
                            <th>Small</th>
                            <th>Medium</th>
                            <th>Large</th>
                        </tr>

                        <tr>
                            <td>USA</td>
                            <td>2-4</td>
                            <td>6-8</td>
                            <td>9-12</td>
                        </tr>

                        <tr>
                            <td>UK</td>
                            <td>4-6</td>
                            <td>8-10</td>
                            <td>12-14</td>
                        </tr>

                        <tr>
                            <td>India</td>
                            <td>2-4</td>
                            <td>6-8</td>
                            <td>10-12</td>
                        </tr>
                    
                    </table>
            
                ";

                foreach( $categories as $cat ){
                    if( 15 == $cat->term_id ) {
                        echo $content;
                    }
                }
   
        }