MIAMI (NewsNation Now) — In Miami Thursday, ballot drop boxes at voting locations were busy with voters hand delivering their ballots.

“I’m here just to be one hundred percent sure it is going to be counted today. Not to have to check online and see is it counted, is it not. I felt more secure doing this here,” Miami resident Antonio Martinez said.

More than a dozen states allow voters to mail-in their ballot up until Election Day.

The states include Alaska, California, Illinois, Kansas, Kentucky, Maryland, Massachusetts, Minnesota, Mississippi, Nevada, New Jersey, New York, North Carolina, Pennsylvania, Virginia, Washington, and West Virginia.

The mail-in ballots must be postmarked by November 3.

But this late in the game – some elected officials say it is best to hand-deliver mail-in ballots, or vote in person.

“Even the Postal Service is saying now it is too late to mail. A first-class piece of mail could take more than five or six days to get to the destination. That speaks for itself,” Speaker of the House Nancy Pelosi said Thursday.

The U.S. Supreme Court refused Republicans’ effort to block a three-day extension for counting absentee ballots received by election day in Pennsylvania.

The high court also refused to block a similar extension in North Carolina.

But in Wisconsin, the court ruled ballots must arrive by election day to be counted.

Around the country, canvas boards, like one in Polk County, Florida are working long hours.

It is their job to go through the mail-in ballots and make sure voter signatures on ballot envelopes match up with the signature on file.

“The minute we identify there might be a problem, that the signature might not match and the ballot is not signed, we immediately reach out to the voter and let them know how they can fix that,” Polk County Supervisor of Elections Lori Edwards said.

In Florida, more than 7 million people have already voted. That is about half of registered voters.