Tax Resident versus Tax Non-Resident:
The U.S. tax system distinguishes between tax residents, subject to the same tax rules as U.S. citizens and permanent residents, and tax non-residents. Most international students and scholars are initially considered tax non-residents, particularly during their early years of studying or residing in the U.S. For example, F-1 students typically fall into the tax non-resident category for the first five years of their physical presence in F-1 status. Your tax residency status affects how taxable income is defined, your eligibility for tax benefits (including tax treaty benefits), and the amount of tax that may be withheld from your income or other taxable earnings.
Federal & State Tax:
U.S. income taxes operate at both federal (national) and state levels. While the U.S. federal government and states generally follow the same tax calendar, there can be variations in tax regulations between the federal government and different states. For instance, federal taxes are administered by the Internal Revenue Service (IRS), while each state, such as Pennsylvania, has its own set of tax requirements managed by its respective Department of Revenue.