If she receives social security benefits, she will automatically receive her stimulus by direct deposit to her bank account.
This is an extract of a IRS document.
Economic Impact Payments: What you need to know
Updated April 1, 2020
The distribution of economic impact payments will begin in the next three weeks and will be distributed automatically, with no action required for most people. Social Security beneficiaries who are not typically required to file tax returns will not need to file to receive a payment. Instead, payments will be automatically deposited into their bank accounts. However, some taxpayers who typically do not file returns will need to submit a simple tax return to receive the stimulus payment. When more specific details become available, we will update the coronavirus page.
Edited 04/02/2020 | 11:36 PM PST
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