GONNA start an business so, i need an answer these for million dollar question

Hello, i wanted to start an Dropshipping business under a company registered in India where i will Dropship only to tier 1 countries from other country. Here the goods wont come to or go from India. Pay is accepted from the customer will be via Paypal business account in my website with that amount i will take my profit and place order to the supplier in a website ( light in the box ) where the supplier take my order and he will ship to the customer with invoice. I will also send an invoice to my international customer for paying me under my company. For paying to the supplier website, i have to pay only in Dollars $ from my credit or debit card.the placing order will be fully automated from an authorized third party app. He will not send any invoice to me directly from his company and i have to use that transaction as receipt. I have an option to download all the receipt for the orders that i had placed to the supplier website under an third part app installed to my website. 1) All the transaction will be in Dollars only for that do i need an RBI approval ?? 2) since, i wont get any invoice to me for buying products from the supplier will there be any issue?? 3) as i am doing these stuff do i need an llp or pvt ltd for limited liability ?? I know these stuff is an legal one and many ppl r doing it but i have these doubt to start so help me for answering these million dollar question regards,