EXE files and apis

I want to insert some code at the beginning of a code segment of a .exe file so the application will close when this code will execute.I could write a illegal operation like 00 00 00 and the application will close becouse it tried to execute an illegal instruction.But i want to use windows API's to close the application.I want to use Exitproces API function but i don't know how to call it.
Can i find out the address of ExitProces function by looking in the PE header or how ?