What deadlines do you need to know to vote by mail?
"One is the deadline to register if they haven't already done so. Two is the deadline for asking to vote by mail, if they haven't already done so. And three is when the deadline is for getting that mailed ballot back. That's probably the most important deadline," said David Hawkings, the editor-in-chief of The Fulcrum.
In nine states and Washington D.C., all registered voters will automatically receive their November ballot in the mail. Everywhere else, voters need to request a mail-in ballot. But some states, like Minnesota, don't have a deadline to do that.
"We have no deadline in Minnesota, which means that someone could technically order a ballot mailed to them the day before the election. That's not a very smart strategy," said Minnesota Secretary of State Steve Simon.
In 30 states, mail-in ballots must be received on or before Election Day. In most other states, late arriving ballots are still counted, as long as they're postmarked by Nov 3.
Millions of Americans expected to vote by mail for the first time this year. The US Postal Service put out its own recommendations, telling voters they should allow at least one week for their ballots to be returned by mail.
"Even though it's I think pitched as a convenience or luxury for voters to be able to vote by mail, it does come with complications in terms of having to start earlier to cross all the T's and dot all the I's," said Barry Burden, director of the elections Research Center, University of Wisconsin-Madison