Sub replaceTxts()
    Dim fso As New FileSystemObject, curFolder As folder, curFile As File
    folderPath = "C:\5000\"
    Set curFolder = fso.GetFolder(folderPath)
    For Each curFile In curFolder.Files
        If Right(curFile.Path, 4) = ".txt" Then
            curFile.Copy Replace(curFile.Path, ".txt", ".csv")
            curFile.Delete
        End If
    Next curFile
End Sub

Set fso = CreateObject("Scripting.FileSystemObject")

Sub Мяу()
    Dim oldName$, newName$, fName$
    fName = "C:\Новая папка (2)\"
    oldName = Dir(fName & "*.txt", vbDirectory)
    Do While oldName <> ""
        newName = Replace(oldName, ".txt", ".csv")
        Name fName & oldName As fName & newName
        oldName = Dir
        DoEvents
    Loop
End Sub

Sub XML_Âûãðóçêà()
    Dim fso As Object
    Dim txt As Object
    Dim cell As Range
       Set fso = CreateObject("Scripting.FileSystemObject")
    Set txt = fso.CreateTextFile("C:\1.XML", True, True)
    For Each cell In Range("M36")
        txt.WriteLine cell
    Next
     
    txt.Close
    Set txt = Nothing
    Set fso = Nothing
   
End Sub