Oklahoma: How to vote, where to vote and what’s on the ballot.

It’s Election Day in Oklahoma. Here’s a last-minute guide to voting in the state’s primary elections.

How to vote

Polls are open until 7 p.m. local time in Oklahoma. Registered voters waiting in line at polling locations at that time will still be able to vote.

In order to vote, you will need to show one of several forms of ID, including a state or tribal identification card, driver’s license or passport.

If you are voting by absentee ballot, you must have your signature notarized before you return it. Ballots must be received by 7 p.m. on Election Day.

Where to vote

You can find your closest polling place and check if you are registered to vote by visiting the secretary of state’s website here.

What’s on the ballot

Voters will weigh in on a special election to replace Senator James M. Inhofe, a Republican who is retiring. Representative Markwayne Mullin is hoping for the G.O.P.’s nomination in that race. Fourteen candidates are competing in the Republican primary to take over the seat Mr. Mullin is vacating.

A sample ballot is available online here.