iPhone XS and iPhone XS Max are scheduled to arrive on September 21. Now, people in the US who pre-ordered one have started receiving notifications that their iPhones are shipping from the warehouses, right now.
Now, people are taking their time to decide that whether to buy one or no. Though the stock has been exhausted Apple.com says that if you order now, the phone will ship in 1-2 weeks. With that said, AT&T offers to deliver the new iPhone units between September 26 and 28. Besides, T-Mobile Chooses to deliver between September 26 and October 2 (even later for the XS Max). Only Verizon seems ready to deliver new pre-orders by tomorrow.
Now, very similar conditions can be seen in other 29 countries. People have to wait a week or two before a unit can be delivered. So, if you are not in the US then, the new iPhone XS and XS Max will start shipping in 29 more countries.