Your question isn't entirely clear, so I'll give three answers.
If you're referring to what opens when you open Code::Blocks itself, go to the Settings
menu, then click Environment
. Make sure you're in the General Settings
section of the sidebar; change On application start-up
to Open blank workspace
.
If you're referring to what shows up when you create a new project, @Blorgbeard's link has a (slightly dated) picture showing how to create a new project template. Set up a project the way you want it, then open the File
menu and click Save project as template
.
If you're referring to what shows up when you create a new file in your project, go to the Settings
menu, then click Editor
. Scroll to the Default code
section of the sidebar; whatever you enter here will be set as the default contents for any C++ source file (or any C++ header file) you create.