Dim SheetName As String
SheetName = InputBox("What sheetname do you want to use?")
If SheetName <> "" Then
    If Not WorksheetExtant(SheetName) Then
        Dim ws As Worksheet
        Set ws = ThisWorkbook.Worksheets.Add(Type:=xlWorksheet)
        With ws
            .Name = SheetName
        End With
        ActiveWorkbook.Save
        MsgBox "Worksheet " & SheetName & " Created successfully"
    End If
End
Else
    MsgBox "Action Cancelled"
End If