Choose Format - Arrange - Send Backward (LibreOffice Writer, LibreOffice Calc).
Choose Shape - Arrange - Send Backward (LibreOffice Draw).
Command Ctrl + λΉΌκΈ° κΈ°νΈ(-) (LibreOffice Impress, LibreOffice λλ‘μ°)
Open context menu - choose Arrange - Send Backward (LibreOffice Impress).