Regarding global income taxation, if you are a US citizen or resident living outside the USA, your worldwide income is subject to US income tax, regardless of where you reside. This is also known as double taxation. There are specific exclusions on foreign-earned income that you should check to see if you are eligible.
Most countries impose rules and stipulations related to worldwide tax liabilities, so be aware of these differences between countries.
The IRS (Internal Revenue Service) is responsible for helping taxpayers understand and meet their income tax responsibilities, including enforcing the law if the taxpayer attempts to fall short of their tax duties.