Just a FYI
My daughter did not get the second stimulus check. She got direct deposit for the first one. The online tracker just says payment status unavailable, still. They are no longer updating that system.
We sent in our 2019 tax year 1040s in the same FedEx envelope early on in the tax year. Mine was processed and I got a refund last June. She was not expecting a refund so didn't do any checking on it.
Yesterday she phoned the IRS number for overseas taxpayers as she couldn't get through on the ones for people in the USA and they had no record of her having filed a 2019 tax return. Since the 2019 was the one they slurped bank and address info off of to generate the 2nd stimulus payment, she, thus, got no payment. The IRS person said they were still processing 2019 tax returns but that she should consider sending in a duplicate at some point. (Since she owed no taxes, that shouldn't be a problem.) They also manually changed her address in their system. We are not sure if that will be enough to generate a payment for her for the upcoming $1,400 stimulus check or not. (We both sent in change-of-address forms to the IRS in early January. Obviously those are not yet processed. Since our last 1040 address was out of the country, we cannot set up/access any of the "do it yourself online" systems for requesting tax transcripts, etc..)
My hunch is that they ripped open the FedEx envelop and one smaller envelope fell out, and they didn't notice there was another one in there and just tossed the envelope (with her 1040) away into the trash.
I filed my 2020 1040 4 weeks ago, but it took 2 weeks to get to the IRS via certified mail. (Whose online system still doesn't show as it having been opened/received. In a good year they say to allow 4 to 6 weeks for processing.) I filed head-of-household, which should actually generate her $1,400 to my account. IF the return is processed before they do the direct deposits. Otherwise, there's a possibility that I will have to wait until next year's 1040s go in to claim the credit for her.
Bottom line - if you filed a paper 1040 with the IRS last year, even if you have a "delivered" receipt from your courier of choice, and if you have not heard anything or did not expect to hear anything but want to check on your status, you might want to try to get a tax transcript for the 2019 tax year to make sure they actually have your info. Had my daughter realized her 1040 had not been processed, she could have gone to the IRS's online portal to register her info for the stimulus check back when that portal was open, and would then probably have gotten a payment.
I have been urging her to file online this year, immediately, even though she has no income and owes nothing, so that she can get a direct deposit since it's highly unlikely my 1040 will be processed before they start distributing the stimulus payments and neither she nor I will get the $1,400 for her.