If you did not receive the stimulus payments you can use the Rebate Credit on Form 1040 Line 30

[question everything]

Quite convoluted, with a long form to complete which, frankly, I skipped.

Still, from the IRS page

https://www.irs.gov/newsroom/recovery-rebate-credit

The Recovery Rebate Credit is authorized by the Coronavirus Aid, Relief, and Economic Security (CARES) Act and the COVID-related Tax Relief Act. It is a tax credit against your 2020 income tax. Generally, this credit will increase the amount of your tax refund or decrease the amount of the tax you owe.

The Recovery Rebate Credit was eligible to be paid in two rounds of advance payments during 2020 and early 2021. These advanced payments of the Recovery Rebate Credit are referred to as the first and second Economic Impact Payments.

Individuals who received the full amounts of both Economic Impact Payments do not need to complete any information about the Recovery Rebate Credit on their 2020 tax returns. They already received the full amount of the Recovery Rebate Credit as Economic Impact Payments. You received the full amounts of both Economic Impact Payments if:

Your first Economic Impact Payment was $1,200 ($2,400 if married filing jointly for 2020) plus $500 for each qualifying child you had in 2020; and.
Your second Economic Impact Payment was $600 ($1,200 if married filing jointly for 2020) plus $600 for each qualifying child you had in 2020.

Who can claim the Recovery Rebate Credit?

Eligible individuals who did not receive the full amounts of both Economic Impact Payments may claim the Recovery Rebate Credit on their 2020 Form 1040 or 1040-SR. To determine whether you are an eligible individual or the amount of your Recovery Rebate Credit, complete the Recovery Rebate Credit Worksheet in the Instructions for Form 1040 and Form 1040-SR.

You must file Form 1040 or Form 1040-SR to claim the Recovery Rebate Credit even if you are normally not required to file a tax return. Anyone with income of $72,000 or less can file their Federal tax return electronically for free through the IRS Free File Program.