The IRS mails paper checks to taxpayers who elect to have their tax refunds mailed to them, as stated by the IRS website. Tax payers are also able to receive their refunds via direct deposit. Both paper check and direct deposit refunds are usually issued within 21 days from the date the IRS receives the tax return.
Tax payers are able to track the status of their paper checks or direct deposit refunds by using the "Where's My Refund?" tool on the IRS website.
The IRS permits three refunds to go into the same financial account. Refunds in excess of this amount are automatically issued via a paper check.