There are a few different ways that you can change a text file to a flat file. One way is to use a text editor, such as Notepad++, and open the file. Then, go to the "Convert" menu and select "Convert to ANSI". This will save the file as a flat file.
Another way is to use a converter tool, such as the Flat File Converter from CodePlex. This tool will take a variety of different file types and convert them to a flat file format.
Once you have the file in a flat file format, you can then use a variety of different tools to work with it. For example, you can use a text editor to view and edit the file, or you can use a flat file database, such as Microsoft Access, to store and manipulate the data.