For example, for my 2022 Roth IRA contribution, for the money I am going to contribute, does it matter if I earned the money today (like, Jan 15, 2023) instead of earned it during 2022? Or I can only contribute the money that I earned during 2022 to my 2022's limit?
Thanks!
An IRA contribution for 2022 is not permitted to be more than your compensation for 2022 (box 1 or your 2022 W-2 or net earnings from self employment in 2022). However, cash is fungible, so it doesn't matter where you get the cash to make the deposit.
In other words, specific dollar bills don't have name tags telling where they came from or when they were earned. And you can designate contributions for the 2022 tax year up until April 15, 2023 (make sure to tell the bank in advance if you want to make a 2022 contribution). But the overall amount you contribute for the 2022 tax year can't be more than your 2022 compensation from working.