Can any one from india? How Does GST Works!?

You receive an invoice from Apple as shown in the pic below.

Procedure for Filing Refund Request

Any taxpayer can claim a refund of any tax, interest, penalty, fees or any other amount paid by him by filing an application electronically in FORM GST RFD-01 through the GST Common Portal or through a GST Facilitation Centre.

How to Get GST Refund? - IndiaFilings

Also, you may look at this for help --> Step-by-Step Guide to GST Refund Claims - ClearTax

Taxes are included in all prices for these countries and regions: Albania, Armenia, Australia, Austria, Belarus, Belgium, Bulgaria, China mainland, Croatia, Cyprus, Czech Republic, Denmark, Egypt, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, India, Ireland, Italy, Japan, Republic of Korea, Latvia, Lithuania, Luxembourg, Malta, Netherlands, New Zealand, Norway, Poland, Portugal, Romania, Russia, Saudi Arabia, Slovakia, Slovenia, South Africa, Spain, Sweden, Switzerland, Taiwan, Turkey, the United Arab Emirates, and the United Kingdom.

I am not sure what you mean by discount, immediately after saying GST.