A non alphanumeric character is any symbol that is not a letter (A–Z) or a number (0–9). Examples include characters like @, #, %, &, *, !, and $. These symbols are commonly used in passwords, coding, databases, and software systems to improve security and formatting. Many websites require non alphanumeric characters in passwords because they make accounts harder to hack. In programming and technical tools, these characters also perform special functions and commands within systems.