[newmanships]

US companies do withhold money from each paycheck, but this varies not just by how much you make, but also by how many dependents you have and a few other things [0]. The US also has default deductions, or a person can choose to itemize. These vary if you are "head of household", single, married. However then there's all kinds of other deductions and things to complicate your tax return such as retirement accounts, mortgages, kids, side income, student loan interest, interest earned and on and on. Would be great if it was easier. :)

[0] https://www.irs.gov/pub/irs-pdf/fw4.pdf

Edit: People who are contractors / not employees have to remember to set aside a portion of their income that the employer would take out automatically for them.