Some programs like Microsoft Excel require a Byte Order Marker (BOM) at the front of an imported file to signal that its content is in UTF-8 format, capable of displaying an international character set.

If you need to generate a BOM in App Inventor, you can do so using the Web1.HTMLTextDecode block.

You will need to drag a Web component into the Designer window, to make this block available, even though you might not be using the Web in your app.

The sequence  will be decoded by the Web1.HTMLTextDecode block into a two byte BOM value and returned by this BOM value procedure for use where you need it.


Once you have a BOM value, you can strip it off incoming file text as needed ...

Strip BOM

You can also add your own BOM to the front of your text as it goes out to a file ...

Save File with BOM