This story is part of Elections 2020, CNET’s coverage of the run-up to voting in November.

On Nov. 3, with the country still reeling from the effects of the coronavirus pandemic, record numbers of Americans are expected to vote by mail to avoid the crowds at their local polling places. For those who prefer to cast their ballot in person, however, states will allow that too, but voters should expect confusion about the location of polling places, long lines and social distancing.

Most states already allow mail-in voting, and in 2016 nearly a quarter of ballots were cast by mail. But this year a handful of states are taking additional steps to make it easier to use a mail-in ballot to vote this fall.

The process started this spring with primary elections, when states began adjusting the way people could safely cast their vote, either in person or by mail. So far, the results have been mixed.

In Georgia, for example, a shortage of poll workers, new polling procedures and a surge in mail-in votes created delays in primary voting. Likewise, in Pennsylvania, election officials were still counting votes a week after its June 2 primary, which saw an increase in mail-in ballots and an unexpected jump in votes cast at polling stations. And in New York’s recent primary, with more than 10 times the number of mail-in ballots received over recent elections, election officials are still counting absentee ballots six weeks after the election, the New York Times reported.

To head off bigger problems in November, many states are urging eligible voters to sign up now for mail-in ballots alongside other plans to hold safe elections. Here’s how states are preparing for the uncertainties of voting this fall. To register to vote in your state, head to the federal government’s voting website to find out how to register and check your registration status.

What is mail-in voting?

The idea of voting by mail is straightforward. You receive your ballot in the mail, complete it at your convenience at home, then put the prepaid envelope in the mail in time for the election.

Across the US, postal voting is widespread. According to Open Source Election Technology Institute — a nonprofit election-research firm — every state offers some form of mail-in voting, ranging from absentee ballots limited to those unable to vote in person to a 100% mail-in voting system used by five states. Here more on the differences between mail-in and absentee voting.

At the state level, mail-in voting is a bipartisan effort: 22 states with Republicans governors offer vote-by-mail options to all voters as do 24 states led by Democratic governors, the election institute said. Four other states require voters to meet certain criteria to vote by mail, such being over 65 or out of the area on election day. To check the rules governing your state’s mail-in voting, head to the federal government’s voting website and follow the links to you state.

Why are state and federal officials talking about postal voting now?

Holding a national election under the best of conditions can be challenging. But as some state primaries have shown, voting during a pandemic can strain a state’s election resources and present challenges for citizens to cast votes while practicing safe social distancing.

To up the ante, in 2016, an estimated 138 million people voted in the November general elections. A report prior to the start of the pandemic predicted up to 160 million voters could participate this fall. Health authorities are already warning that without effective treatments, the US could see a rise in infections this fall, creating a surge of both infections and voter turnout.

If election officials can make it easier for tens of millions of voters to cast their ballots safely from home, fewer people will show up in person to vote, which could help slow the spread of disease.

What are the benefits of mail-in voting?

Voting by mail has other benefits besides helping people practice social distancing.

A mail-in election can be cheaper to run: Colorado, which is 100% vote by mail, cut election administration by 40% after it switched to mail-in ballots.

It can increase voter turnout: According to a Utah study, voting by mail can result in higher voter turnout. In the Georgia primary, some voters stepped out of long lines instead of waiting to vote. Lines could be worse in November, increasing the frustration of voting in person.

They increase voter engagement on more initiatives and candidates: From the same Utah study, those who voted by mail filled out more of their ballots then those who voted in person.

They are convenient: Voting by mail can save you from taking time off from school or work to travel to your polling station and stand in line to vote. You can also send in your ballot days and weeks ahead of an election if voting on the day of the election is inconvenient or impossible.

What are the arguments against voting by mail?

Despite the system’s advantages, some have raised flags about mail-in voting.

Concerns of mail fraud: President Donald Trump has repeatedly talked about the risks of voter fraud with mail-in ballots.

While cases of mail-in voter fraud exist, such as in a 2018 North Carolina election, the instances are extremely rare, said Amber McReynolds, CEO of the National Vote at Home Institute, and Charles Stewart III, the director of the MIT Election Data and Science Lab.

Writing for The Hill, the two reported that in the last 20 years, there have been 1,100 criminal convictions for voter fraud. Of that, 143 were for mailed ballots. That works out to one case per state every six or seven years, the two wrote, or about 0.00006% of total votes cast over 20 years. To dig into the details, the Heritage Foundation keeps a sampling of recent election fraud cases. States also use a variety of methods to ensure the integrity of mail-in ballots, including signature verification and post-election audits.

May benefit one party: Trump has also suggested that voting by mail could benefit democratic candidates. Whether voting by mail benefits one party or not, a study this spring out of Stanford University found that while voting by mail increases turnout rates modestly, it has no discernible effect on increasing vote shares for either party. The New York Times also found no evidence to support the claim that mail-in ballots favored neither party. And recent surveys suggest that Trump’s attacks on mail-in voting could suppress voting for his own Republican party.

May not be available to everyone: A report by the National Conference of State Legislatures found that citizens who move frequently or live in areas without street addresses can be at a disadvantage with a mail-in system.

Postmarked rules applied differently at the state level: While some states accept a ballot postmarked before election day — even if it arrives after the election — a majority of states don’t count mailed-in ballots unless they arrive by the election.

Some states may not be ready to handle mail-in ballots by November: States shifting to mail-in ballots will need to design, print and distribute the ballots and then train both voters and election officials on how to use and count ballots. States that already use a mail-in system have spent years preparing for this. States that are just now shifting to the process may have just months to get ready for a surge in mail-in ballots.

How are states and districts handling postal voting this year?

While every state offers some form of postal voting, the rules for who gets to vote and how varies state by state. Five states entirely vote by mail and send an absentee ballot to each registered voter; on the other end, four states require voters to submit an application with an excuse to be able to receive a ballot by mail. In between are no-excuse states that send an mail-in ballot to anyone who requests one, without a reason.

What about voting in person?

As some primary elections held this year have already shown, voting in a pandemic can be challenging, with long lines and understaffed polling places causing delays. But even with a push to get voters to cast their ballots by mail, states will still allow them to show up and vote.

Hawaii, for example, is one of the five states that vote entirely by mail. It also offers voting centers for those who prefer to vote in person. But don’t expect voting in person to be like previous elections.

Election officials predict a shortage of poll workers for the November election, and some in California — which will conduct the November general election entirely by mail-in ballot — have put out the call for younger voters to help run polling places, which are historically run overwhelmingly by older citizens who this year are at higher risk for infection.

For more: See our guide to the 2020 elections.

What about voting online?

While some states let voters cast their ballots online for state and local elections, in federal elections, you can’t vote online and will need to vote either in person or through the mail this November.

For more details, here are the differences between mail-in voting and absentee voting, why the pandemic may get worse before it gets better and what part social media may play in the fall election.