Where number is currency id in HostBill,In HostBill currency ID depends on the order in which you've added the currencies:
- 0 - is default currency you've set
- 1,2... are next currencies
So The order links:
How to get currency ID?
To get the currency ID go to Settings → Currency & Tax Settings → Additional currencies and hover your mouse over the red Edit button. At the bottom of the page the currency ID will be displayed at the end of the URL: