wordpress insert value in metabox from custom textbox

hi i am new for wordpress, i have crete a custom textbox in woocommerce/includes/admin/meta-boxes/views/html-order-item.php.

id; $_SESSION["itemID"] = $item_id; ?>`enter code here` id, $_SESSION["itemID"],wc_clean($_POST[ '_trans_id' ])); ?>

textbox trans_ID created by manually

this is my result show in database, metavalue is empty