Copy Values from Multiple Columns to 2 Columns

Sub test()    Dim lastCol As Long, lastRowA As Long, lastRow As Long, i As Long


    'find last non empty column number'
    lastCol = Cells(1, Columns.Count).End(xlToLeft).Column


    'loop through all columns, starting from column B'
    For i = 2 To lastCol
        'find last non empty row number in column A'
        lastRowA = Cells(Rows.Count, "A").End(xlUp).Row
        'find last non empty row number in another column'
        lastRow = Cells(Rows.Count, i).End(xlUp).Row


        'copy data from another column'
        Range(Cells(1, i), Cells(lastRow, i)).Copy
        'paste data to column A'
        Range("A" & lastRowA + 1).PasteSpecial xlPasteValues


        'Clear content from another column. if you don't want to clear content from column, remove next line'
        Range(Cells(1, i), Cells(lastRow, i)).ClearContents
    Next i


    Application.CutCopyMode = False
End Sub