Now my question is, where does Lazarus take the template from when I do press the [OK] button?
$lazarusdir/ide/projectdescriptortypes.pas
Do you mean something like this https://wiki.freepascal.org/Project_Templates ?
I give up. Even when I show a picture of where I would like to modify something I get answers that not lead in the direction that I need.
The projtemplates package is to add your own templates using simple description files. Some other packages also add additional project templates using code like the core templates do.
Thanks again for your help, everything works like I wanted it to be.
Can you please help me again, this time I searched for the template that is generated when I click on "Application" (a LCL template)
I wanted to insert one line in the class template where it generate "private" and "public" line.
The .lpr file is in file that you mentioned but I do not find where it takes the .pas file for "unit1.pas" template.