In the back-end

• goto settings in the top menu
• then in the left menu, you goto users.
• Select your user account
• press the edit button
• check that you have access for:

Technical settings.
website   Manage website and qWeb view
click the save button

• refresh your page.

• then goto settings. (at the menu to the left)
• choose Reports (under the Technical section).
• choose Reports (right below Paper format).
• scroll down and find the following report (or search for) invoices)
• select that one.
• in the next screen choose the edit button.
• then change the report type from PDF to HTML.

Now when you print a quotation/order you will get an html file instead of pdf. In fact it will open a new windows with the report as it is generated. At the top of the windows you can change/edit the output of the report.

• Now you can use the edit button and change the report according your wises.
• save the changes.
• After you have made your changes, you can change the report format back to pdf.

if you find this answer helpful, please give me a thumbs up vote (so in the future I can attach some screenshots, to make it easier to understand)!

Thank you very much your answer. Now I can change the html formats of the invoice but there is only few things as I understand. For instance I would like to fix the columns. In turkey we must use pre-prepared paper for the invoices. So we should print out all things in the correct place on the pre-prepared document. Could you please help me also for this issue.

I have try to vote you but I need something(karma) that I don’t understand to vote someone.. I think after few post I can do that..