Different character encoding exists such as ASCII, ISO 8859-1. Nowadays, UTF-8 is the most used because it represents many different characters , including those of different languages, symbols and special signs.
Objectives
Ensure that all characters are encoded by UTF-8 to avoid display issues
Ensure accurate representation of characters
Implementation
Configure UTF-8 production tools and databases as default character encoding
Set UTF-8 to the charset attribute of the meta tag
Control
Check the source code of the HTML page of epub : The meta tag with the charset attribute must be defined on UTF-8 and is in the head tag of the HTML page