I live in Washington, which has all-mail voting, so some of this doesn’t apply here. But it’s very applicable in all the key battleground states. From USA Today (read article here):
The right to vote free of intimidation
18 USC §594 makes it a federal crime to intimidate, threaten, or coerce, or attempt to do so, any person “for the purpose of interfering with the right of such other person to vote or to vote as he may choose.” Voters encountering or witnessing such actions “are encouraged to call the Election Protection Hotline at 866-OUR-VOTE (866-687-8683), or the U.S. Department of Justice voting rights hotline at 1-800-253-3931, or if violence is threatened, call 911 (i.e., local police).
The right to vote by provisional ballot if your name is not on the list of registered voters
First, before going to vote, confirm your registration and poll location. Then, if you’re told your name isn’t on the list of registered voters, you have the right to vote with a provisional ballot, which “should be counted when officials confirm you are a registered voter in that county and you did not vote elsewhere.” Reasons why an eligible voter might not be on the poll list include, “They may have been unlawfully purged, removed from rolls, or error on the part of officials who failed to include a voters’ name on the rolls.’’ In such cases, voting provisionally is worth the effort; 71% of the 2.4 million provisional ballots cast in 2016 were counted.
The right to vote with accomodations
Voters with disabilities are legally entitled to voting access, and to voting assistance, if needed. For example, “Any voter unable to reach the polling site because of physical limitations or architectural barriers may request a ballot ‘curbside.’ A polling site worker brings a ballot or a voting device to the voter and, if necessary, assists the voter.” In addition, there are legally-prescribed accomodations for limited-English speakers, and toll-free numbers for help in Spanish (1-888-839-8682), Arabic (1-844-925-5287) and Bengali, Catonese, Hindu, Urdu, Korean, Mandarin, Tagalog and Vietnamese (888-274-8683).
The right to vote after the polls close
If you’re still waiting in line at poll closing time, you have the right to vote, and can’t be turned away, no matter how long it takes for you to get inside to vote.
The right to re-vote
Once you cast your ballot, you can’t change it, or vote again. But up to that moment, you have the right to correct mistakes or change your mind. Thus, “if you make a mistake, like voting for the unintended candidate or voting or more than one person for a single office, ask a [poll worker] for help. Replacement ballots are available.”