A Roth IRA is a type of investment savings account that lets an investor invest money for retirement without paying taxes on the money after funding the account, notes CNN Money. Investors fund their Roth IRAs with after-tax pay, meaning that they pay taxes on the money prior to putting it into the IRA, so they don't worry about paying it later.
There is no tax on a Roth IRA as the money in the IRA grows, notes CNN Money. When the investor reaches retirement, there is also no tax on the IRA when funds are withdrawn. With a traditional IRA, the investor has the option to delay paying taxes on the money in the account until he retires.