How to convert a report into excel sheet

PROCEDURE U_1ButtonAction is
CURSOR cur is
  SELECT A.EMP_CODE,A.EMP_TITLE ||' '||A.EMP_FNAME ||' '||A.EMP_LNAME EMP_NAME,A.EMP_DEPT,A.EMP_TYPE,EMP_DOJ
FROM BPAYT030 A WHERE A.EMP_TYPE = DECODE(:P_EMPTYPE,'A',A.EMP_TYPE,:P_EMPTYPE)
AND A.EMP_DEPT = DECODE(:P_EMPDEPT,'A',A.EMP_DEPT,:P_EMPDEPT)  AND EMP_STATUS ='Y';
--AND A.JOB_TITLE  = DECODE(:P_JOB,'A',A.EMP_DEPT,:P_JOB)
V_OUTFILE TEXT_IO.FILE_TYPE;
V_OUTSTRING    VARCHAR2(1000);
L_FILENAME     VARCHAR2(100);
L_SR           NUMBER:=0;
L_DESC         VARCHAR2(200);
L_DESC1        VARCHAR2(200);
BEGIN
L_FILENAME := 'C:'||'EMPLOYEE LIST'||TO_CHAR(SYSDATE,'DDMMRR')||'.CSV';
 V_outfile := text_io.fopen(L_FILENAME,'W');   
 V_outstring := ','||','||'EMPLOYEE TYPE/DEPARTMENT WISE DETAILS';
TEXT_IO.PUT_LINE(V_OUTFILE, V_OUTSTRING);
V_outstring :='';
TEXT_IO.PUT_LINE(V_OUTFILE, V_OUTSTRING);
V_outstring := :P_COMP;
TEXT_IO.PUT_LINE(V_OUTFILE, V_OUTSTRING);
  --EXCEL FILE HEADS
 V_outstring :='EMPLOYEE TYPE'||','||'DEPARTMENT'||','||'CODE'||','||'DOJ' ||','||'EMPLOYEE NAME';
TEXT_IO.PUT_LINE(V_OUTFILE, V_OUTSTRING);
FOR REC IN CUR LOOP
SELECT CODE_DESC INTO L_DESC FROM BCOMT011 WHERE TYPE_CODE  = REC.EMP_TYPE;
SELECT CODE_DESC INTO L_DESC1 FROM BCOMT011 WHERE TYPE_CODE  = REC.EMP_DEPT;
--DATA IN EXCEL
V_outstring :=  L_DESC||','||L_DESC1||','||REC.EMP_CODE||','||EC.EMP_DOJ||','||REC.EMP_NAME;
TEXT_IO.PUT_LINE(V_OUTFILE, V_OUTSTRING);
END LOOP;
text_io.fclose(v_outfile);
SRW.MESSAGE(100,'File '||L_FILENAME|| ' Generated Successfully....');
EXCEPTION      
WHEN OTHERS THEN
SRW.MESSAGE('1',SQLERRM);
text_io.fclose(v_outfile);
END;

What is a stored procedure ?

A stored procedure is a subprogram that is stored in the database as a PCODE and thus called as a standalone schema object.

a) It can be invoked directly from any calling environments, or other subprograms.

b) It is similar to any subprogram that accepts parameters and performs an action. It may or may not return a value. This attribute differentiates it from another subprogram type called FUNCTION.

c) It can be nested

d) Is created by using the syntax CREATE OR REPLACE

e) This stored procedure can be seen as an object in the User_Objects and is different from the procedures that are created in packages.

Is it possible to use Transaction control Statements such a ROLLBACK or COMMIT in Database Trigger ? Why ?

Generally In triggers you can't use TCL commands.
But you can use TCL commands in Autonomous Triggers.
You can declare a trigger as Autonomous by providing PRAGMA AUTONOMOUS_TRANSACTION in the beginning of the trigger.
At a same time you have to end your trigger with commit/rollback.
You can use these type of triggers to maintain log details of a table.