This is a very complicated topic with many nuances we will not be able to cover in a knowledge base article.
However, the short answer is that everyone is required by law to pay some amount of income tax on any US-source income received, no matter who you are and where you’re located.
If you are a nonresident alien, you will be responsible for income tax on any US-source income you receive. Assuming January 2019 rates, your tax obligation starts at roughly 30% before being reduced by a nonrefundable tax credit equal to the amount of income tax you pay in your home country on that same income. You’ll need to file an IRS Form 5472 on behalf of the company (i.e. LLC) every year and will need to file an IRS Form 1040NR (Nonresident Tax Return) on your own behalf. You’ll likely need to obtain an Individual Taxpayer Identification Number (TIN or ITIN) by filing IRS Form W-7 before completing your first tax return.
You should consult with a CPA or Accountant in your native country that understands income tax issues locally and the US. If you need advice from a US-based CPA or Accountant, please check our Preferred Partners page.
Please read our other knowledge base articles on this topic entitled, Do Non-Residents / Non-US Citizens Have to File Income Taxes in the US When They Own an Anonymous LLC? and I am not a US Citizen, but want to form an Anonymous company in the US and have a US-based bank account, so I have a lot of tax questions.