The US tax regulations for non US citizens can be difficult and confusing.  We have extensive experience in helping non US citizens comply with those regulations and the associated paperwork.
THE MOST COMMON PROBLEMS FACED BY NON US CITIZENS INCLUDE:

Individual Taxpayer Identification Number (ITIN) and/or Employer Identification Number (EIN).

Foreign Investment in Real Property Tax Act (FIRPTA).

United States Real Property Investment (USRPI).

Activities Effectively Connected With A US Trade or Business.

Withholding Requirements  On Funds Transferred Out Of The US.

Estate (Death) Tax Issues.

US Nonresident Alien Income Tax Return For Individuals And Trusts.

State Sales And Other Taxes.