Once your return has been mailed, you cannot change your option on how you receive your refund. If you need banking information for the stimulus money, see the following.
The IRS does not have my direct deposit information. What can I do?
In the coming weeks, Treasury plans to develop a web-based portal for individuals to provide their banking information to the IRS online, so that individuals can receive payments immediately as opposed to checks in the mail.
https://www.irs.gov/newsroom/economic-impact-payments-what-you-need-to-know
