Tira here, from Shopify.
I'm happy to help.
I want to ask some questions to understand what it is that you're looking to do.
What payment method are you using on your store? If you don't have a payment method set-up yet, check out our list of payment providers in India.
Are you looking to set-up taxes on your store? This will very depending on your location. For GST in India, you can check out the steps and details in our help doc, here: GST in India. Shopify has default tax rates for India, so you will have to adjust these rates to fit what you need. Check out some examples here: How do I set-up my taxes?