Formatting text file in AppleScript

There's a fundamental flaw in your premise: A plain txt file can't have formatting.

That's the very definition of plain text: unformatted. If you apply formatting, the text is no longer plain.

There are many different ways to apply formatting to text, but they all involve adding extra data, called markup or formatting codes. Two examples are HTML and RTF.
http://en.wikipedia.org/wiki/Html
http://en.wikipedia.org/wiki/Rich_Text_Format

Another approach would be simplified markup text embedded in plain text, which is later interpreted to produce other formats. An example is Markdown:
http://en.wikipedia.org/wiki/Markdown

Any of these formats can be produce by concatenating the desired text with the appropriate markup codes.


You said you're creating receipts from CSV, but you didn't say what the receipts are for. Please describe the entire process, so we have an idea of what the overall goal is, as well as its scale.