The IRS issued three stimulus payments (two in 2020 and one in 2021). It's too late to claim the Recovery Rebate Credit for 2020 and 2021. The IRS began issuing payments to eligible people who didn't claim the Recovery Rebate Credit on their 2021 tax returns, so you don't need to do anything to get these payments.
Review the IRS website Recovery Rebate Credit for more information.