By default, any report that you generate and download from the Administrator Dashboard on the Web Portal will be in CSV format. CSV files are just plain-text, comma-separated values and do not come with a specified text-encoding. It is up to the application that opens the CSV file to choose the appropriate encoding. Interestingly, most simple programs such as Windows Notepad will automatically open the file with the correct text-encoding.
However, if you try to open a CSV file with Microsoft Excel by simply double-clicking on it, the local encoding will be used by default, and it may not be the desired one. For example, if you are in the United States with English keyboard and you try to open a document containing Japanese characters, the document might open with 1252 Western European Windows codepage and render like this:
In order to render non-English characters correctly in Microsoft Excel, you should go to the Data menu and import "From Text/CSV" from the ribbon.
Choose the CSV file from your hard-drive. Then, in the wizard popup window, choose 65001 Unicode (UTF-8) codepage.
After you click on the Load button, the characters will be displayed correctly and even some colored styles will be applied by default by Microsoft Excel.