Standards: Something that is widely used by everyone so that everyone can find it easy to use and adapt. Such as a keyboard layout, cables, and knowing what combination of number represent which characters.
ASCII (American Standard Code for Information Interchange) is a standard character encoding used in telecommunication. The ASCII pronounced ‘ask-ee’, uses seven-bits which can represent 128 characters.
ASCII codes are used to represent alphanumeric data.
When we talk about ASCII, we usally refer to "Extended ASCII" - which uses 8-bits. So 256 characters can be represented.
Unicode is another character set. It uses 16 bits.
Unicode can represent over 65,000 characters from different languages and scripts. We have loads of space left which is now being used to store emojis.