Hello Sherwin.
If you wish to send only constant then try below logic
PARVW--------------------
Equals--------------------------IF
Constant------------------- -----------------------------------BillFromID
(AG) Constant----Then
(JHAH)
If you wish to send only constant JHAH with PARTN Concatenated then try below logic
PARVW--------------------
Equals--------------------------IF
Constant------------------- -----------------------------------BillFromID
(AG)
Constant
(JHAJ) --------
Concat------------------Then
PARTN----------------------