To make use of OExport add the OExport, OExport_Vcl and OExport_VclForms (alternatively OExport and OExport_FMX if you use FireMonkey) units to the uses clause of your unit and create a TOExport object.
Furthermore do not forget to set the OExportDateFormat and OExportTimeFormat global variables.
A simple code snippet for a basic XLSX document would be:
uses OExport, OExport_Vcl, OExport_VclForms; procedure CreateDocument(const aFileName: String); var xExport: TOExport; begin xExport := TOExport.Create; try with xExport.AddWorkSheet('simple types') do begin AddRow; with AddRow do begin AddCellString('string').SetWidth(200); AddCellString('my "custom" string').SetWidth(400). SetAlignment(taCenter).SetBorders(cbAll, ebThick, clGreen). SetBorder(cbBottom, ebDouble, clRed); end; with AddRow do begin AddCellString('integer'); AddCellNumber(15, 0); end; with AddRow do begin AddCellString('float'); AddCellNumber(15.7812, 2); end; with AddRow do begin AddCellString('formula'); AddCellFormulaNumber('B3+100*B4', 2); end; with AddRow do begin AddCellString('date'); AddCellDate(Now); end; AddRow; with AddRow do begin AddCellString; AddCellString('cell spanned over 3 columns and 2 rows').SetColSpan(3).SetRowSpan(2). SetVAlignment(cavCenter).SetAlignment(cahCenter).SetBorders(cbAll, ebMedium, clBlue). SetBGColor(clYellow); end; end; xExport.SaveToFileWithDialog; finally xExport.Free; end; end; initialization OExportDateFormat := OEXPORT_SYS_DATE; OExportTimeFormat := OEXPORT_SYS_TIME; end.