So, if you're working with CSV, what special characters are supported?
There are no restrictions on what characters you can use in a CSV file. The limitation is the way the file is encoded.Here is an article
on choosing the right encoding, UTF-8 is the recommended encoding for the file because it supports almost every possible character. If you don't choose UTF-8, chances are you'll run into the "??????" error or you will see in your cells something similar to "Ê∏ÖÂ¥é" or "–§–æ–º–∞".
Problems with special characters and encoding usually occur when you open the CSV in another program (i.e., not a regular text editor). When you see lots of question marks instead of your data software informs you that it has no idea which characters to display to you.
For example, if you try to open CSV in Excel, you will likely see the "??????" or other unrecognized data. To avoid that, you need to import CSV files into Excel using the special wizard to display data correctly. Go to "Data" tab and select "Get External Data". Choose "From Text".