difference between #include and #include “file”

#include <file>

This variant is used for system header files. It searches for a file named file in a standard list of system directories.
Example :

#include <stdio.h>
int main()
{
	printf("include system header files from default directory");
	return 0;
}

#include “file”

This variant is used for header files of your own program. It searches for a file named file first in the directory containing the current file, then in the quote directories and then the same directories used for <file>.
Example (for including custom header files):

#include <stdio.h>
#include "myHeader.h"

int main()
{
	printf("%d", multipliedBy3(2));
    return 0;
}

Custom header file (myHeader.h) in same directory

int multipliedBy3(int);

int multipliedBy3(int temp)
{
	return temp * 3;
}