How do I change the delimiter when copy-pasting from Excel?

I don't think there's any way of changing the default delimiter character (i.e. Tab) used while copying text to the clipboard from Excel. What you can do however is create a macro to achieve the result you want.

  1. Create a macro named something like CopySelectedCells and optionally assign a keyboard shortcut so you can invoke it quickly (I assigned it Ctrl+Shift+C for example):

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  2. From the main Macro dialog shown above, click the Edit button to open the VBA Editor.

  3. Go to Tools menu / References and click on the Browse button.

  4. Add Windows\System32\FM20.dll:

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  5. Select the Microsoft Forms 2.0 Object Library option now added to the Available References list:

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  6. Edit the macro code to look like the following:

    Sub CopySelectedCells()
        Dim str As String
        For Each rangeRow In Selection.Rows
            For Each rangeCol In rangeRow.Cells
                str = str & rangeCol.Value & ","
            Next
            str = Left(str, Len(str) - 1) & vbCrLf
        Next
    
        With New DataObject
            .SetText str
            .PutInClipboard
        End With
    End Sub
    
  7. Close the VBA Editor, select a range of cells and invoke the macro, then paste in Notepad to see the comma-separated result.