Using VBA (Visual Basic for Applications) , you can create Excel workbook at the runtime by using Add() method.
If you won’t provide any name for the workbook it will be created as BookN, where N will increase automatically, starting from 0, as you call WorkBook.Add() function.
Function FnCreateWorkBook() Dim objWorkBook As Workbook Set objWorkBook = Workbooks.Add objWorkBook.SaveAs Filename:="NewWorkBook.xls" End Function