Option Explicit
Sub testcomplet()
Dim F1 As Variant
Dim F2 As Variant
Dim W1 As Workbook
Dim W2 As Workbook
Dim rng As Range
Dim cel As Range
F1 = Application.GetOpenFilename("Excel File (*.xls;*.xlsx),*xls;*.xlsx", , "Source")
If F1 = False Then Exit Sub
MsgBox "Le fichier source sélectionné est :" & vbCr & F1
F2 = Application.GetOpenFilename("Excel File (*.xls;*.xlsx),*xls;*.xlsx", , "Destination")
If F2 = False Then Exit Sub
MsgBox "Le fichier destination sélectionné est :" & vbCr & F2
Set W1 = Workbooks.Open(Filename:=F1)
Set rng = W1.Worksheets(1).Range("A1").CurrentRegion
Set W2 = Workbooks.Open(Filename:=F2)
With W2.Worksheets(1)
Set cel = .Cells(1, .Columns.Count).End(xlToLeft).Offset(, 1)
End With
rng.Copy Destination:=cel
W2.Save
W2.Close
W1.Close
End Sub