The procedure is a subprogram which can take parameters and be invoked. Normally, you can use a procedure to perform an action. The procedure has 2 sections: the specification & the body.
The specification starts with the keyword PROCEDURE and ends with the procedure name or a parameter list. The Parameter declarations are not obligatory. The Procedures that take no parameters are written without the parentheses. The procedure body starts with the keyword IS and ends with the keyword END followed by an elective procedure name.
The procedure body has 3 sections: an optional declarative section, an executable section, & an optional exception-handling section. The declarative section consists of declarations of the types, constants, cursors, variables, exceptions, &subprograms. These items are local and cease to exist whenever you exit the procedure. The executable section consists of statements which assign the values, manipulate Oracle data, and control execution. The exception-handling section contains the exception handlers that deal with the exceptions raised during execution.