Text encoding is an applied instance of [binary encoding](/Hardware/Binary/Binary_encoding.md).
There are around 100 characters in total required to render A-Z, a-z, 0-9 and special characters. The ASCII (American Standard Code for Information Interchange) system achieves this with 8-bit code. Thus, each character symbol corresponds to a byte. As $2^8 = 256$. This allows for a total of 256 characters (where only 7-bits are sufficient, a leading `0` is added).
Below are some examples of the ASCII correspondences: