why type def is used in c code example

Example 1: typedef in c

typedef struct
{
  	//add different parts of the struct here
 	string username;
  	string password;
}
user; // name of struct - you can name this whatever

user example; //variable of type user

example.username = "Comfortable Caterpillar"; // username part of example variable
example.password = "password" // password part of example variable
  
if (user.username == "Comfortable Caterpillar")
{
	printf("upvote this if it helped!");
}

Example 2: man typedef

typedef enum 
{
	false,
    true
}Bool;