i am a non-resident U.S. Alien.
i incorporate a LLC in Delaware for my online e-shop purpose.i sold physical products to U.S. customers only.=======> You can start a business in Delaware from anywhere in the world.Since you formed a corp in DE, your corp will be taxed as like any other US corp. The corp will pay the same taxes that any other US corp would on all US-sourced income and your DEcorp would also be taxed on all foreign earnings, in accordance with US Treasury regulations. Since your corp was formed in the US, it is taxed as a domestic corp and you will file Form 1120 with the IRS.
i bought products from china and send to U.S. customer directly from china==>OK as mentioned above, since you have U S source income you need to file your corp return with the IRS.