Odoo does not have a built-in standard report to directly show sales by vendor and product, but you can use product vendor information in the Sales Analysis report by filtering or grouping sales data based on the product's vendor. This can be done through the Sales > Reporting > Sales Analysis pivot view with customized filters, and if needed, minor customizations or community modules may enhance this capability.

To send monthly statements to suppliers showing customer-wise sales of their products, the usual method is to export sales or invoice data filtered by each vendor’s products and group it by customer and product. This approach uses Odoo’s standard export and reporting tools or available third-party modules to generate detailed sales statements for suppliers regularly and accurately.

Hi,

Please refer to the module:

https://odoo-community.org/shop/sale-report-filter-by-product-suppliers-5290#attr=7909

This module allows filtering by product supplier in the sales reports to obtain the sales for that specific set of products.

Hope it helps.