What payment method and tax documentation do I need for drop shipping in the USA from Pakistan?

[vox14196]

Hello kind Members,

My name is Rashid. I am a resident of Pakistan and I want to start drop shipping over shopifty and my targeting marketplace is USA. I have Few questions in mind before starting 
Firstly, as I am living in Pakistan and i want to sell in USA so what payment method should i use for store. i do have a Payoneer account with USA router number And i heard that we can use Payoneer as payment method to withdraw funds.
Secondly, What about tax and duties ? is shopify gonna ask for tax documentation information ? if yes. what should be the documents for it? 
At third, i was viewing the subscription plans for shopify and i see this " 

Shopify Marketplace Connect

First 50 orders from shopify synced listings are free, then 1% per synced order up to $99 per month (USD)." what does this mean?
lastly, i have heard that shopify app is a key source of getting order. does it effect my listing on shopify app  that i am Pakistani resident and selling in USA.

I am looking forward to the crew members kinds response and assistance on my concerns.
kind Regards,
Rashid