Window-creation functions create, destroy, modify, and obtain information about windows. The following list briefly describes each window-creation function:
| Function | Description | |
| AdjustWindowRect | Computes the size of a window to fit a given client area. | |
| AdjustWindowRectEx | Computes the size of a window with extended style to fit a given client area. | |
| CreateWindow | Creates overlapped, pop-up, and child windows. | |
| CreateWindowEx | Creates overlapped, pop-up, and child windows with extended styles. | |
| DefDlgProc | Provides default processing for those dialog-box messages that an application does not process. | |
| DefFrameProc | Provides default processing for those multiple document interface (MDI) frame window messages that an application does not process. | |
| DefMDIChildProc | Provides default processing those for MDI child window messages an that application does not process. | |
| DefWindowProc | Provides default processing for those window messages that an application does not process. | |
| DestroyWindow | Destroys a window. | |
| GetClassInfo | Retrieves information about a specified class. | |
| GetClassLong | Retrieves window-class information from a WNDCLASS structure. | |
| Function | Description | |
| GetClassName | Retrieves a window-class name. | |
| GetClassWord | Retrieves window-class information from a WNDCLASS structure. | |
| GetLastActivePopup | Determines which popup window owned by another window was most recently active. | |
| GetWindowLong | Retrieves information about a window. | |
| GetWindowWord | Retrieves information about a window. | |
| RegisterClass | Registers a window class. | |
| SetClassLong | Replaces information in a WNDCLASS structure. | |
| SetClassWord | Replaces information in a WNDCLASS structure. | |
| SetWindowLong | Changes a window attribute. | |
| SetWindowWord | Changes a window attribute. | |
| UnregisterClass | Removes a window class from the window-class table. |