in the standard product form, have a look at the supplier section. There are fields there for supplier code. Also the main product form has a field for reference or code.

Not sure if they are searchable by standard but you can add easily enough

regarding supplier/Customer Code: apparently there is something called "Contact Reference" which is existing inside of odoo. Weirdly this seems to be invisible and unsearchable for the user by default.

Forunately someone (Daniel Reis - thank you!) made a module called crm refcodes that pulls these entries out of the database and makes them visible and searchable for the users. Testing this for a very short time I have seen though that this works best when you add these "Contact Reference" in the moment a Contact is being created. When I tried to add them to an existing Supplier or Customer they are not displaying in the list or kanban view and I could only find them using "advanced search" > Contact Reference contains ..." When you added this while dreating the contact you can just type in a value in the regular search field and odoo will find all entires that use the string you entered in the "Contact Reference"

Lucky me. I am only beginning to use this

Hi Gunnar,

There is no need to build two modules, you can create just one custom module to add those required fields (product code and supplier code) and respected search views into the product form. Those fields can be called on all the required views like Kanban, search views etc. Product reference number or product code is already their but its only for internal reference, so additional field can be added to give supplier defined product code.

For any help or queries feel free to contact me (akhil.p.sivan007@gmail.com)