Hi Bilguudei,

It's a report action, that is added in the following way (by the "sale" module):

You can found out more in the Odoo official documentation.

Best regards, Yurii Razumovskyi.

Company Garazd Creation — Odoo solutions for e-commerce, SEO, Data Feeds, Website Tracking, Marketing and Analytics integrations, Product Label designing and printing.

https://garazd.biz

Hi 

The function _get_report_values will call when we print the Report. It returns the data that needs to be printed in the Report

Check this reference to call a function while printing the Report

How To Call A Python Function While Printing PDF Report in Odoo

Regards