Je viens de trouver la solution, merci d'avoir consulter
Sub CompléterChaine()
Dim x As Integer
Dim C As Range
For Each C In Range("a2:a" & Range("a" & Rows.Count).End(xlUp).Row)
x = Len(C)
If C.Value <> "" And Len(C.Value) < 8 Then
Select Case x
Case 1
C.Offset(0, 1) = C.Value & "0000000"
Case 2
C.Offset(0, 1) = C.Value & "000000"
Case 3
C.Offset(0, 1) = C.Value & "00000"
Case 4
C.Offset(0, 1) = C.Value & "0000"
Case 5
C.Offset(0, 1) = C.Value & "000"
Case 6
C.Offset(0, 1) = C.Value & "00"
Case Else
C.Offset(0, 1) = C.Value & "0"
End Select
End If
Next C
End Sub
End Sub