Sample of API FND_PROFILE

1. FND_PROFILE.GET(‘Name of the Profile’, variable name);

SELECT fnd_profile.value('PROFILEOPTION')
      ,fnd_profile.value('MFG_ORGANIZATION_ID')
      ,fnd_profile.value('ORG_ID')
      ,fnd_profile.value('LOGIN_ID')
      ,fnd_profile.value('USER_ID')
      ,fnd_profile.value('USERNAME')
      ,fnd_profile.value('CONCURRENT_REQUEST_ID')
      ,fnd_profile.value('GL_SET_OF_BKS_ID')
      ,fnd_profile.value('SO_ORGANIZATION_ID')
      ,fnd_profile.value('APPL_SHRT_NAME')
      ,fnd_profile.value('RESP_NAME')
      ,fnd_profile.value('RESP_ID')
  FROM DUAL;

2. variable name := FND_PROFILE.VALUE(‘Name of the profile’);

3. FND_PROFILE.PUT(‘Name of the profile’, value of the profile);

SET SERVEROUTPUT ON;
DECLARE
   v_conc_login_id      NUMBER;
BEGIN
   FND_PROFILE.put ('CONC_LOGIN_ID',1425);
   fnd_profile.get ('CONC_LOGIN_ID', v_conc_login_id);
   DBMS_OUTPUT.put_line (v_conc_login_id);
END;
Output:
1425
PL/SQL procedure successfully completed

FND_PROFILE.GET is the procedure and FND_PROFILE.VALUE is the function so, it return a value. 

4.FND_PROFILE.SAVE used to set the profile values from backend.

The table fnd_profile_options_tl, profile options names are kept.  Now find the corresponding the Profile option name for which you need to update from backend. For this example I took my favorite “ORG_ID”

SELECT profile_option_name
  FROM fnd_profile_options_tl
  WHERE user_profile_option_name LIKE 'MO%'

It returns more than one row but i can make out that "ORG_ID" is the PROFILE_OPTION_NAME for MO: Operating Unit. Now I need to know the Org_ID of the Org whose value is to be set in MO: Operating Unit. SO I use the simple select as below

SELECT organization_id , NAME
  FROM hr_all_organization_units;

From the organization name I find the one which will be the default Operating Unit, and I note the ID. In my case the ID for my default Operating Unit is 286. Now with the code below I set the profile option value using fnd_profile.save.

DECLARE
   stat   BOOLEAN;
BEGIN
   DBMS_OUTPUT .DISABLE;
   DBMS_OUTPUT .ENABLE ( 100000 );
   stat : = fnd_profile .SAVE ( 'ORG_ID' , 286 , 'SITE' );
    IF stat
   THEN
      DBMS_OUTPUT .put_line ( 'Stat = TRUE - profile updated' );
   ELSE
      DBMS_OUTPUT .put_line ( 'Stat = FALSE - profile NOT updated' );
   END IF;
    COMMIT;
END;

5.fnd_profile.defined
IF (fnd_profile.defined('TRANSACTION_DATE')) THEN
  l_profile_value := TO_NUMBER(fnd_profile.value('TRANSACTION_DATE'));
  ....

source:http://www.shareoracleapps.com/2011/05/profile-options-in-oracle-apps-r12.html