Functional currency and presentation currency
1C:Drive supports accounting in one currency only: the presentation currency.
At that, you can keep records of mutual settlements with your counterparties in different currencies - in the presentation currency and in the counterparty currency / contract currency.
The functional currency is only used to pre-fill the counterparty currency / contract currency in documents.
It is the presentation currency that 1C:Drive uses when posting entries to its registers.
So, as the presentation currency, you should use the currency in which you want to keep accounting records.
For instance, if you accept payments in both USD and INR and you need to submit mandatory tax reports in INR, set the presentation currency to INR.