From a press release:
The Social Security Administration announced today that Supplemental Security Income (SSI) recipients will automatically receive their Economic Impact Payments directly to their bank accounts through direct deposit, Direct Express debit card, or by paper check, just as they would normally receive their SSI benefits. Treasury anticipates SSI recipients will receive these automatic payments no later than early May.
This means that SSI recipients with children as well as those with pending disability claims who have not filed a tax return for 2018 or 2019 still need to file the "tax returns" but that's a much smaller problem.
“SSI recipients with no qualifying children do not need to take any action in order to receive their $1,200 economic impact payment. The payments will be automatic,” said Secretary Steven T. Mnuchin. “Recipients with qualifying children should use the ‘Non-Filers: Enter Payment Info Here’ web portal to enter basic information so they can receive their payments as quickly as possible.” ...