HI Venkat,
To be able to update NAV for Mutual Funds, you'll first need to set up Exchange in SAP. The Path for the same is Securities -> Basic Settings -> Define Exchange
Before Defining Exchange, please make sure the below settings are in place:-
Define countries by choosing General Settings -> Set Countries -> Define Countries
Maintain calendar ID by choosing General Settings -> Maintain Calendar
Check currency codes by choosing General Settings -> Currencies -> Check Currency Codes
Once the Exchange has been maintained, you should be able to update the NAV using Transaction Code FW17. You can then run TPM1 to calculate MTM.
Please let me know if you need further clarifications.
Regards,
Rohit