Sub DeleteRowsMultipleWorkBooks()
Dim directory As String, filename As String
'Directory, where all your needed workbooks are
directory = "C:\Users\Username\Documents\My_examplefolder\"
filename = Dir(directory & "*.xl??")
'Do-loop trough all files stored in directory
Do While filename <> ""
Workbooks.Open (directory & filename)
With Workbooks(filename)
Sheets(1).Rows("1:6").Delete
.Save
.Close
End With
filename = Dir()
Loop
End Sub