By default odoo sets the default company for all objects/views from the user's session i.e Sales Order,Invoice Purchase etc, This default company doesn't set on contacts and partners. Default Company on Contacts and Products Odoo App helps users to set default company on product and contacts. While any user creates or imports products and contacts, Current user's company is set as the default company.

Create or Import Products

While any user create or import products, Current user's company should be set as default company.

While user switch into another company and create or import products then also current user's company should be set as default company.

Create or Import Customers/Contacts

While any user create or import customers/contacts, Current user's company should be set as default company.

While user switch into another company and create or import customers/contacts then also current user's company should be set as default company.