For information about the structure of INI files and how they store information (sections, keys and values), see the tutorial: Implementing Configuration Files for Computer Based Data Acquisition Systems
The above code can be integrated into your application with 2 button, 1 for reading data and 1 for writing data. Use a Case structure
or Event structure
to trigger the code when the button is selected.
There are many possible ways to read and/or write to files in LabVIEW. INI files is just 1 solution. Many different file formats can be used.