A6. Under a new law enacted in December 2020, a married couple filing a joint return now may be eligible for a partial credit when only one spouse has a Social Security number valid for employment. if you and your spouse did not receive one or both Economic Impact Payments because one of you did not have a Social Security number valid for employment, you should complete the Recovery Rebate Credit Worksheet or use tax preparation software to determine if you may claim a Credit on your 2020 tax return for the spouse with the Social Security number valid for employment.  if eligible for a Recovery Rebate Credit, you claim it on line 30 of your 2020 tax return.
https://www.irs.gov/newsroom/recovery-rebate-credit-topic-b-eligibility#militaryssn