Difference between write() and printf()

Question

Recently I am studying operating system..I just wanna know:

What’s the difference between a system call (like write()) and a standard library function (like printf()

Answer 1

System Call's in OS are used in interacting with the OS. E.g. Write() could be used something into the system or into a program.

While Standard Library functions are program specific, E.g. printf() will print something out but it will only be in GUI/command line and wont effect system.

Sorry couldnt comment, because i need 50 reputation to comment.

EDIT: Barmar has good answer