RE: how to update LCY to my local currency
In BC Standard there is no way to set this up.
In many tables, like the customer or vendor ledger entries you'll find fields like Amount [which means this the amount in transaction currency / foreign currency ... if a currency code has been entered] and Amount (LCY) ... here we don't show "Amount (MYR) [in your case] but always the generic ... "Amount (LCY)".
If you want to chenage that a customization would be needed