Set here in the menu: file/advanced save options/unicode utf8;

Signed means that the file header contains encoding information.

EF BB BF, these three byte codes for this file are UTF8 encoded.

FF FE: Indicates that this is UTF16 LE (little endian) encoding.

FE FF: represents UTF16 BE (big endian).

For detailed information, you can check the UNICODE encoding specification.