Hi,
In Odoo 18.4, when you only install Accounting, the vendor bill line shows Label instead of Product.
This is by design: Odoo expects you to use the line just for descriptions unless the Purchase or Inventory module is installed.
To be able to select products directly on vendor bills, you need to enable product management.
The minimal way is to go to Apps and install the Product app (sometimes called "Products" / "Inventory" base module).
If you don’t want full Purchase flows, you don’t need to install the Purchase module—just install Products so that product fields are available.
After that, the vendor bill lines will show the Product column instead of just Label.
If you keep only Accounting, you can’t get product dropdowns—only free text descriptions.
So the solution is: install Products (or Inventory) module → activate product tracking → you will see products again in vendor bills.
Hope it helps