According to the federal government, people with children under 17 years of age who don't file tax returns and who receive Supplemental Security Income (SSI) will automatically start receiving a $1,200 stimulus payment from the IRS soon. 

But they're also able to receive an additional $500 for each qualifying child under 17 as long as they complete the necessary information by May 5.

To complete that information, they must visit the IRS Non-Filers: Enter Payment Info  webpage and turn in all required information as quickly as possible.