Thanks Dawid. The problem isn't finding the place where to change the code. It's completely unclear and undocumented what I have to change in which template. There is so much inheritance that I can't find where for instance the code is that formats the address.

You want the address format in Odoo 18 Online to look like this:

[Company Name]  
T.a.v. [Contact Name]

instead of the default:

[Company Name], [Contact Name]

Solution

Since you are on Odoo 18 Online (SaaS), you don’t have access to the backend code, but you do have Odoo Studio, which is enough to customize reports and fields.

Option 1: Customize Report Template in Studio

1. Open any report (e.g., Quotation, Invoice).
2. Click Edit with Studio.
3. Locate the Address Block that prints the partner’s details.
4. Replace the content with:

   ${object.parent_id.name or ''}    ← Company Name
   T.a.v. ${object.name or ''}       ← Contact Name
   

   parent_id = company, name = contact.

Option 2: Create a Custom Field with Computed Value

If you want this format as a field you can reuse:

1. In Studio, create a new field (e.g., “Formatted Address”).
2. Set it as a Computed Field with this formula:

   (record.parent_id.name or '') + '\nT.a.v. ' + (record.name or '')