Thank you all for the replies. I will try both methods! Thank you!

Hi,

In odoo13, in the tree view there is option to select which all fields has to be displayed in the tree view/one2many tree view, hope you are talking about this in the first part of the question.

In the case of the print outs, we don't have such options, the report is generated from the qweb template, so if you need to make any changes in the existing reports, you have to inherit the corresponding template and make necessary changes.

See an example of how the sale report is inherited:

<template id="sale_report_inherit" inherit_id="sale.report_saleorder_document">
    <xpath expr="//div[@class='row mt32 mb32']" position="after">
         <div class="row mt32 mb32" id="test_inherit">
            <div class="col-auto mw-100 mb-2">
                <strong>Test Report Customization:</strong>
            </div>
         </div>
    </xpath>
    <!--<xpath expr="//div[@class='row mt32 mb32']" position="replace">-->
    <!--</xpath>-->
</template>

Also the template can be adjusted from the user interface from settings in the developer mode.

Settings -> Technical -> Reporting -> Reports, search for the report,lets consider the case of sale report, search for sales, then you will see corresponding reports, open the record, in the top right you will see a button named Qweb View, click to see the templates used in the report, you can edit and make changes in the templates, but it will be lost once you upgrade the sales module. So it is suggested to add a new view from the UI or to achieve it from the code.

Also you can see this example: How To Inherit And Modify Existing PDF Reports in Odoo

Thanks

Hello Xleaaron

The qweb views you can find by settings -> technical -> reports ->reports.
Find the report name and after that you see a link to the qweb view. This one you can change and the effect is imediatly in print report.