Adding Indian Currency in Opencart is really simple. Just follow the steps or watch Video How to Add a INR as New Currency in OpenCart 3.x and make it default Currency below it will hardly take 3 minutes.
For Adding Indian Currency INR Go to
System > Localization > currencies
Create new Currency with the following details
Currency Title – Indian Rupee
Code – INR
Symbol Left – ₹
Decimal Places – 2
Status – enabled
Now Changing INR as default default currency … Go to
System > Settings > Local (Tab)
change Country, Region / State, Currency
Watch Video How to Add INR as New Currency in Opencart 3.x and make it default Currency
I think its very simple, this was successfully tested on Open Cart 2.X,3.X , if you have any problem then let me know through comments or register on my website to discuss.