Private Sub CommandButton1_Click()
    Dim text, out As String
    Dim k, n, latinCount, nonLatinCount, r, t, p As Integer
    Dim textArray() As String
    Dim latinPositions(), nonLatinPositions() As Variant
    latinCount = 0: nonLatinCount = 0: r = 0: t = 0: p = 0

    text = ReadFromFile("Текст1.txt")
    n = Len(text)
    ReDim textArray(n - 1)
    ReDim latinPositions(n - 1)
    ReDim nonLatinPositions(n - 1)

    For k = 0 To n - 1
        textArray(k) = Mid(a, k + 1, 1)
        Next k

    For k = 0 To n - 1
        If textArray(k) Like "[A-Z]" Or textArray(k) Like "[a-z]" Then
            latinCount = latinCount + 1
            latinPositions(r) = k
            r = r + 1

        ElseIf textArray(k) Like " " Or textArray(k) Like "." Then
            p = p + 1

        Else
            nonLatinCount = nonLatinCount + 1
            nonLatinPositions(t) = k
            t = t + 1
        End If
    Next k

    If latinCount >= 1 Then
        For n = 0 To (latinCount - 1)
            textArray(latinPositions(n)) = "4"
            Next n
    Else
        For n = 0 To (nonLatinCount - 1)
            textArray(nonLatinPositions(n)) = "4"
            Next n
    End If

    For k = 0 To Len(text) - 1
        out = out & textArray(k)
        Next k

    ' MsgBox (d)
    Call WriteToFile("Текст2.txt", out)
    MsgBox(d)

End Sub

Private Sub IsMoreLatins(ByRef text() As String)
    For k = 0 To n - 1
        If textArray(k) Like "[A-Z]" Or textArray(k) Like "[a-z]" Then
            latinCount = latinCount + 1
            latinPositions(r) = k
            r = r + 1

        ElseIf textArray(k) Like " " Or textArray(k) Like "." Then
            p = p + 1

        Else
            nonLatinCount = nonLatinCount + 1
            nonLatinPositions(t) = k
            t = t + 1
        End If
    Next k
End Sub

Private Function ReadFromFile(ByRef fileName As String) As String
    Dim fso
    Dim file
    Dim readedString as String

    Set fso = CreateObject("Scripting.FileSystemObject")
    Set file = fso.OpenTextFile(fileName, 1)
    readedString = file.ReadAll
    file.Close
    MsgBox("Input: " & a)

    ReadFromFile = readedString
End Function

Private Sub WriteToFile(ByRef fileName As String, ByRef s As String)
    Dim fso
    Dim file

    Set fso = CreateObject("Scripting.FileSystemObject")
    Set file = fso.CreateTextFile(fileName, True, True)

    file.WriteLine(s)
    file.Close
    MsgBox("Output: " & s)
End Sub