The file hasn’t been scrambled. It’s just in ISO-8859-6 encoding, and Notepad++ cannot read it, even though it wrote it. Notepad++ can work with a few encodings only; the large menu for setting encoding is for output only.
Microsoft Word can read the file, but you need to specify the encoding as Arabic (ISO) when opening it. This means ISO-8859-6, which is different from the Windows Arabic encoding, windows-1256.
Alternatively, you could edit the file in Notepad++ and add the following lines at the start:
Then save it with the .html extension and open it in a web browser. You should now see Arabic text, which you can copy and paste.
As a yet another option, download and install the BabelPad editor. Its Open command lets you select the encoding of the file being opened, with ISO-8859-6 as one of the alternatives.
Note: There might be three odd-looking characters at the start of the file, namely the Byte Order Mark (BOM) as UTF-8 encoded, resulting from way the file was written. This reflects the shortcomings of Notepad++.
In general, it is best to work with UTF-8 throughout if possible. This wastes some bytes but saves trouble.