Please help me :
How do I automatically add headers/other things to all new files?
Settings->Editor->Default Code
or if you want only the code in new projects you can modify the template code under CodeBlocksInstallDir/share/Codeblocks/templates
greetings
For the second case (projects), I would suggest to setup a basic project, add everything you need and save it as user template ("File -> Save project as template").