Simple :

find report_saleorder_document report into odoo reports menu.
find code of qweb report code <span t-field="line.name"/> replace it will <td><span t-field="line.product_id.name"/></td>

only report name will come.

This you can do from odoo front end also and create new module and inherit report_saleorder_document report into it and change code.

Change From:

<td name="account_invoice_line_name"><span t-field="line.name"/></td>

Change To:

<td name="account_invoice_line_name"><span t-field="line.product_id.name"/></td>

Hi,

this is because product ref and name are in the same field in sale.order.line model, like : 

'product_id': [152, '[LCLN1131-03] Maxi traversable 15 x 60 cm']

as @Bhaviraj Brahmkshatriya said, edit the report template and use a regex to remove the brackets and its content

Thanks Bhaviraj !

So I tried what you said:

Under report_invoice_document, I changed the line:

See here: https://ibb.co/7bjn7r6

After reloading Odoo under a private window and printing a PDF invoice, here is the result: https://ibb.co/LxYTKjC

So I still have the default_code appearing inside [] brackets. I would like it to disappear. Any idea why it didn't work?