This article explains how you can order items from within a project, if you want to order across multiple projects or have a process where employees request products ordered, you may want to check out ordering across multiple projects.
Order Selected Products for a Project from the BOM view
Within the Project > BOM, you can select products you want to order and select the "Add to order" option to add them to a new or an existing PO for the same supplier in the "Draft" state.

To Start check/select the products you want to order
The product sidebar will open on the right side.
Click the split button in the sidebar in the ordering section
Click the Add to PO option
Order Selected Products for a Project from the Product Status view
Within the Project > under Details tab > Product Status view, you can select products you want to order and use the Actions button > "Add to/Create order" option to add them to a new or an existing PO for the same supplier in the "Draft" state.

To Start check/select the products you want to order
Click on the "Actions" button to the right of "Product Status" label
Select the Add to/Create order option from the menu