var workbook = new XLWorkbook("BasicTable.xlsx");
var ws = workbook.Worksheet(1);

// Get a range object
var rngHeaders = ws.Range("B3:F3");

// Insert some rows/columns before the range
ws.Row(1).InsertRowsAbove(2);
ws.Column(1).InsertColumnsBefore(2);

// Change the background color of the headers
// Notice that rngHeaders point to the right place
rngHeaders.Style.Fill.BackgroundColor = XLColor.LightSalmon;

ws.Columns().AdjustToContents();

workbook.SaveAs("ShiftingRanges.xlsx");