What is Package in Oracle PLSQL

According to Oracle PLSQL is a combination of Procedures, Functions, Cursors, and Exceptions. Putting all these objects in a procedural Language is called a package.

Source: Oracle document

Sample code to create a package

CREATE PACKAGE emp_bonus AS
PROCEDURE calc_bonus (date_hired employees.hire_date%TYPE);
END emp_bonus;
/
CREATE PACKAGE BODY emp_bonus AS
-- the following parameter declaration raises an exception
-- because 'DATE' does not match employees.hire_date%TYPE
-- PROCEDURE calc_bonus (date_hired DATE) IS
-- the following is correct because there is an exact match
PROCEDURE calc_bonus (date_hired employees.hire_date%TYPE) IS
BEGIN
DBMS_OUTPUT.PUT_LINE('Employees hired on ' || date_hired || ' get bonus.');
END;
END emp_bonus;
/