Have you file a 2018 or 2019 tax return and did you enter direct deposit information that is still correct on the tax return? If so, you will get your check direct deposited into that same account.
If you have not filed a return and don't need to, use this web site to register for the payment with direct deposit information: https://turbotax.intuit.com/stimulus-check/
If you filed a return but there was no direct deposit information on it or the bank account information has changed, then you need to enter the correct information on an IRS online portal when it is available around mid April. See this from the IRS: https://www.irs.gov/coronavirus/economic-impact-payments
