Format specifiers in C are placeholders used inside functions like printf() and scanf() to specify the type of data being processed. They always start with the % symbol followed by a character that represents a data type.
These specifiers are extremely important because C is a strongly typed language, and the compiler needs to know:
Think of format specifiers as labels on boxes. Without labels, you don’t know whether a box contains books, clothes, or electronics. Similarly, without format specifiers, C cannot correctly process data.