We can create new application user from existing user with same responsibility, Which can be achieved from FNDLOAD utility.

Here I would like to create new user with name ‘APPADMIN’ (Target user) from existing user SYSADMIN (Source user).
SOURCE USER : SYSADMIN
TARGET USER : APPADMIN

To find the responsibilities of source user:
set pages 1200
set lines 200
SELECT frt.RESPONSIBILITY_NAME, furg.end_date
FROM
fnd_user_resp_groups furg,
FND_RESPONSIBILITY fr,fnd_responsibility_tl frt,fnd_user fu
WHERE fu.user_name = ‘&&username’
AND   fu.user_id = furg.user_id
AND   furg.responsibility_id = fr.RESPONSIBILITY_ID
AND   frt.responsibility_id = fr.RESPONSIBILITY_ID
ORDER BY 1;
 

STEP 1: Use FNDLOAD to download user SYSADMIN from your instance:

FNDLOAD apps/<apps password> 0 Y DOWNLOAD $FND_TOP/patch/115/import/afscursp.lct  SYSADMIN_USER.ldt FND_USER USER_NAME=SYSADMIN

STEP 2: Modify the ldt file (SYSADMIN_USER.ldt for the example above):

Change the line <BEGIN FND_USER “SYSADMIN”> to <BEGIN FND_USER “APPADMIN”>

 
BEGIN FND_USER “APPADMIN”
OWNER = “APPSMGR”
LAST_UPDATE_DATE = “2014/01/06”
START_DATE = “1951/01/01”

STEP 3: Use FNDLOAD to upload new user to your instance:

FNDLOAD apps/apps 0 Y UPLOAD $FND_TOP/patch/115/import/afscursp.lct  SYSADMIN_USER.ldt  FND_USER   USER_NAME=APPADMIN

STEP 4: Change the password of the new user from application and communicate.

 
Thank You !!