Explanation
The Products Consumed section on the Work Order allows the technician to record the products used and adjust the inventory levels of their van stock. The Product Item Transactions Related List on the Product Item shows the history of product movements, but does not allow recording new transactions. The Work Order Line Item associated with the completed Work Order shows the products required, but not the products used. The Product Request Line Item associated with the Product shows the products requested, but not the products consumed. References: https://help.salesforce.com/s/articleView?id=sf.fs_products_consumed.htm&type=5
https://help.salesforce.com/s/articleView?id=sf.fs_product_item_transactions.htm&type=5
https://help.salesforce.com/s/articleView?id=sf.fs_work_order_line_items.htm&type=5
https://help.salesforce.com/s/articleView?id=sf.fs_product_request_line_items.htm&type=5