Следующие функции используются для создания и управления окнами.

AdjustWindowRect
AdjustWindowRectEx
ArrangeIconicWindows
BeginDeferWindowPos
BringWindowToTop
CascadeWindows
ChildWindowFromPoint
ChildWindowFromPointEx
CloseWindow
CreateWindow
CreateWindowEx
DeferWindowPos
DestroyWindow
EnableWindow
EndDeferWindowPos
EnumChildProc
EnumChildWindows
EnumThreadWindows
EnumThreadWndProc
EnumWindows
EnumWindowsProc
FindWindow
FindWindowEx
GetClientRect
GetDesktopWindow
GetForegroundWindow
GetLastActivePopup
GetNextWindow
GetParent
GetTopWindow
GetWindow
GetWindowPlacement
GetWindowRect
GetWindowText
GetWindowTextLength
GetWindowThreadProcessId
IsChild
IsIconic
IsWindow
IsWindowUnicode
IsWindowVisible
IsZoomed
MoveWindow
OpenIcon
SetForegroundWindow
SetParent
SetWindowLong
SetWindowPlacement
SetWindowPos
SetWindowText
ShowOwnedPopups
ShowWindow
ShowWindowAsync
TileWindows
WindowFromPoint
WinMain

Устаревшие функции:
AnyPopup
EnumTaskWindows
GetSysModalWindow
GetWindowTask
SetSysModalWindow