The original objective of Unicode is to use a 16-bit encoding to provide ing for over 65000 characters. However, this is not enough. It cannot cover all historical texts or solve the implantation head-ache problem, especially in network-based applications. The existing software must do a lot of work to program 16-bit data.
Therefore, Unicode uses three encoding methods with some basic reserved characters. They are UTF-8, UTF-16, and UTF-32 respectively. As the name suggests, in a UTF-8, a character is encoded in an 8-bit sequence and represents a character in one or several bytes. The biggest benefit of this approach is that the UTF-8 retains the ASCII character encoding as part of it, for example, in the UTF-8 and ASCII, "a" encoding is 0x41.
The UTF-16 and UTF-32 are Unicode 16-bit and 32-bit encoding methods, respectively. Given the initial purpose, Unicode is typically a UTF-16. When discussing Unicode, it is very important to determine which encoding method is used.