Millions of Americans have received their stimulus checks by now, but when they received them depends greatly on whether or not they were signed up to receive them by direct deposit or paper check. Those who were signed up for direct deposit already since the IRS had their banking information or signed up direct deposit using the IRS portal should have received their checks weeks or even months ago while those who did not have their direct deposit information saved with the IRS had to wait weeks or even months to get their stimulus checks.
Another important thing to keep in mind is that having your taxes updated was a big factor in the first round of stimulus checks, so if you haven't completed your 2019 taxes then you should probably get those done as soon as possible in case a second round of stimulus checks come out soon. People who had their 2019 taxes completed *and* had their direct deposit information already saved with the IRS were the first to get their stimulus checks when they rolled out earlier in 2020 and would be the first to get them if there is a second round of stimulus checks in the future.
So, if you want to be first in line if there is another stimulus check then get your 2019 taxes done as soon as possible and be sure to sign up for direct deposit before you submit them. You'll be thanking yourself later!