Converting from .xlsx to .txt
Your code is incredibly fragile

directory = ThisWorkbook.Sheets("Macro").Range("D576").Value
rdate = ThisWorkbook.Sheets("Macro").Range("E47").Value


If a single row/column gets added or deleted or moved, those ranges are going to move and your code is going to fail completely. 

If you can, those values should be in a dedicated sheet, not buried below 500 lines of other stuff. If not, name your ranges. 



So, let's say you take cell D576 and name it Directory_Path or something similar. Now, rather than

directory = ThisWorkbook.Sheets("Macro").Range("D576").Value


which is incredibly fragile, you can use

directory = ThisWorkbook.Range("Directory_Path").Value


and so long as nobody actually deletes said row/column, that will always point to the right place.



Use With

Rather than re-referencing the same object over and over, you can use a With statement to hold a reference. Like so:

Application.ActiveWorkbook.SaveAs Filename:=xTextFile, FileFormat:=xlText
Application.ActiveWorkbook.Saved = True
Application.ActiveWorkbook.Close


Becomes

With Application.ActiveWorkbook
    .SaveAs Filename:=xTextFile, FileFormat:=xlText
    .Saved = True
    .Close
End With


much clearer and easier to read.



Handle things in the right order

Specifically your Application.[Settings]. Anything *meta* like that should go right at the start and right at the end of the method(s) it applies to. This allows you to confirm, at a glance, what the internal state of your method is and check that things are set/reset correctly. You should also disable Application.EnableEvents and Application.Calculation for significant extra speed. Like so:

Sub xlsxTotxt()

    With Application
        .ScreenUpdating = False
        .DisplayAlerts = False
        .EnableEvents = False
        .Calculation = xlCalculationManual
    End With


    ...


    Code


    ...


    With Application
        .ScreenUpdating = True
        .DisplayAlerts = True
        .EnableEvents = True
        .Calculation = xlCalculationAutomatic
    End With

End Sub




Use descriptive naming

Code should be written for other people (including future you) to read. Names should be descriptive, unambiguous and concise. In that order. I highly recommend the excellent, classic article on naming by Joel Spolsky. But in short, things should sound like what they are. 

xTextFile. What on earth is that? Looking at it I have no idea. If I had to guess, I'd say it's some kind of file object. Oh, it's the filename you want to save your text file under? Why not call it newFilename? Since it's a full filename (including directory path). Maybe newFullfilename or just fullFilename might be even more descriptive.

xWs suffers from the same problem. I can guess it's a worksheet object but beyond that? no idea. Since you just use it to iterate over the sheets in your workbook, maybe just call it currentSheet?

fname. Same thing. filename. Since it's the filename for the workbook you're opening, how about targetWorkbookFilename? Sure, it's long, but screen real estate is cheap, cognitive processing is not and that name's an awful lot easier to understand and work with.

Also, move your declarations near to where they're used. This helps you *see* the different parts of your method and helps you keep track of where you are, refer back to your declarations and see ways to split things up into logical sub-methods. Personally, I prefer to keep declarations outside of Loop structures, but that's personal preference.



Objects are your friend

VBA has a huge, extensive, comprehensive object model for every Office Application. Use it.

ThisWorkbook.Sheets("Macro")


You refer to that sheet multiple times. Rather than continually repeating that reference, put it in a worksheet object and then just refer to the object.

Dim macroSheet As Worksheet
Set macroSheet = ThisWorkbook.Sheets("Macro")

Dim dateString As String
dateString = macroSheet.Range("E47").Value


Same with Workbooks.

Do While ThisWorkbook.Sheets("Macro").Range("D577").Offset(i).Value &lt;&gt; ""
fname = Sheets("Macro").Range("D577").Offset(i).Value
Workbooks.Open (directory &amp; fname)
For Each xWs In Workbooks(fname).Worksheets
xWs.Copy
xTextFile = directory &amp; rdate &amp; " - " &amp; xWs.name &amp; ".txt"
Application.ActiveWorkbook.SaveAs filename:=xTextFile, FileFormat:=xlText
Application.ActiveWorkbook.Saved = True
Application.ActiveWorkbook.Close


Relying on ActiveWorkbook being the one you want is very fragile. Just make it a proper object and then your references will always be accurate:

Dim targetWorkbook As Workbook
Set targetWorkbook  = Workbooks.Open (directory &amp; fname)

...

For Each currentSheet In targetWorkbook.Sheets()

    ...

    With targetWorkbook
        .SaveAs filename:=xTextFile, FileFormat:=xlText
        .Saved = True
        .Close
    End With




Indenting

Indenting is a wonderful way to let you see the structure of your Sub. It'll let you pick out nested-logic (Loops, Ifs, Fors, Withs etc.) and very quickly get a rough idea for where the important stuff in your sub is. Compare:

Do While ThisWorkbook.Sheets("Macro").Range("D577").Offset(i).Value &lt;&gt; ""
fname = Sheets("Macro").Range("D577").Offset(i).Value
Workbooks.Open (directory &amp; fname)
For Each xWs In Workbooks(fname).Worksheets
xWs.Copy
xTextFile = directory &amp; rdate &amp; " - " &amp; xWs.name &amp; ".txt"
Application.ActiveWorkbook.SaveAs filename:=xTextFile, FileFormat:=xlText
Application.ActiveWorkbook.Saved = True
Application.ActiveWorkbook.Close
Next
Workbooks(fname).Close
i = i + 1
Loop


With

Do While ThisWorkbook.Sheets("Macro").Range("D577").Offset(i).Value &lt;&gt; ""

    fname = Sheets("Macro").Range("D577").Offset(i).Value
    Workbooks.Open (directory &amp; fname)

    For Each xWs In Workbooks(fname).Worksheets

        xWs.Copy
        xTextFile = directory &amp; rdate &amp; " - " &amp; xWs.Name &amp; ".txt"

        With Application.ActiveWorkbook
            .SaveAs Filename:=xTextFile, FileFormat:=xlText
            .Saved = True
            .Close
        End With

    Next

    Workbooks(fname).Close
    i = i + 1

Loop


And suddenly you can see your program flow, and where the real work is happening, and where loops start/end, in just a glance. Adding some whitespace also goes a long way to helping readability.



Putting it all together

Sub xlsxTotxt()

    With Application
        .ScreenUpdating = False
        .DisplayAlerts = False
        .EnableEvents = False
        .Calculation = xlCalculationManual
    End With

    Dim parentDirectoryCell As Range
    Set parentDirectoryCell = ThisWorkbook.Range("Directory_Path")

    Dim parentDirectoryPath As String
    parentDirectoryPath = parentDirectoryCell.Value

    Dim dateString As String
    dateString = ThisWorkbook.Sheets("Macro").Range("E47").Value


    Dim fullFilename As String
    Dim currentSheet As Worksheet
    Dim targetWorkbook As Workbook
    Dim targetWorkbookFilename As String

    Dim rowOffset As Long
    rowOffset = 1

    targetWorkbookFilename = parentDirectoryCell.Offset(rowOffset).Value
    Do While targetWorkbookFilename &lt;&gt; ""

        Set targetWorkbook = Workbooks.Open(parentDirectoryPath &amp; targetWorkbookFilename)

        For Each currentSheet In targetWorkbook.Sheets()

            currentSheet.Copy
            fullFilename = parentDirectoryPath &amp; dateString &amp; " - " &amp; currentSheet.Name &amp; ".txt"

            With targetWorkbook
                .SaveAs Filename:=fullFilename, FileFormat:=xlText
                .Saved = True
                .Close
            End With

        Next currentSheet

        targetWorkbook.Close

        rowOffset = rowOffset + 1
        targetWorkbookFilename = parentDirectoryCell.Offset(rowOffset).Value

    Loop

    With Application
        .ScreenUpdating = True
        .DisplayAlerts = True
        .EnableEvents = True
        .Calculation = xlCalculationAutomatic
    End With

End Sub