bonsoir
Supposons que les noms trouvés dans la colonne : A
En utilisant ce code :
Sub Myhotmail()
Dim cl As Range
For Each cl In Range("A1:A" & Cells(Rows.Count, 1).End(xlUp).Row)
X = Application.WorksheetFunction.Find(",", cl)
cl.Offset(, 1) = Right(cl, Len(cl) - X) & "." & Left(cl, X - 1) & "@hotmail.com"
Next
End Sub