Ok you pay taxes on your taxable income ... period And what you do with that income once you pay taxes on it is immaterial. So you could put under the mattress, in a savings account or invest it in the market or cds thru a broker's account or bank account.
Now to reduce your taxable income you could put it into a retirement account of some kind ... maybe an IRA or 401K or something else that is either deductible either on your tax return as an adjustment or at work as a pre-tax contribution.
