sql> create type emp_obj is object (empno number,ename varchar2(10));
  2  /

Type created.

sql> create type emp_tab is table of emp_obj;
  2  /

Type created.

sql> create or replace function all_emps return emp_tab
  2  is
  3     l_emp_tab emp_tab := emp_tab();
  4     n integer := 0;
  5  begin
  6     for r in (select empno,ename from emp)
  7     loop
  8        l_emp_tab.extend;
  9        n := n + 1;
 10       l_emp_tab(n) := emp_obj(r.empno,r.ename);
 11     end loop;
 12     return l_emp_tab;
 13  end;
 14  /

Function created.

sql> select * from table (all_emps);

     EMPNO ENAME
---------- ----------
      7369 SMITH
      7499 ALLEN
      7521 WARD
      7566 JONES
      7654 MARTIN
      7698 BLAKE
      7782 CLARK
      7788 SCOTT
      7839 KING
      7844 TURNER
      7902 FORD
      7934 MILLER