The most standard text encoding is UTF-8.
A Unicode-based encoding such as UTF-8 can support many languages and can accommodate pages and forms in any mixture of those languages. Its use also eliminates the need for server-side logic to individually determine the character encoding for each page served or each incoming form submission. This significantly reduces the complexity of dealing with a multilingual site or application.
A Unicode encoding also allows many more languages to be mixed on a single page than any other choice of encoding.
On Unix systems like Linux and MacOS, most files are in UTF-8 by default.
For .txt, .tsv or .csv file, you can use Microsoft Notepad.
For an .xlsx or .xls file, you can use Microsoft Excel.
Save As (Other Formats)
Unicode Text (*.txt)