Election Day was still a few weeks away, and Renee Smithkors, the long-serving director of elections in Bradford Country, Pa., had already had to call sheriff’s deputies 10 times to deal with people who were showing up at her office riled up by rumors about early voting or mail-in ballots.

“There’s a lot of misunderstanding out there,” Ms. Smithkors said, as her staff processed new voter registrations from behind a bulletproof wall inside the county elections office beside the courthouse in Towanda. “I can’t wait for December, when this will all be over.”

Voting has changed dramatically in Pennsylvania over the last several years, with some changes landing in the closing stretch of this year’s election cycle, stirring confusion, anxiety and tension just a couple of weeks before a presidential election that may be decided by the state’s 19 electoral votes.

In Bradford, a mostly rural county along the state’s northern border, local officials voted last week to reverse a policy that had allowed voters who made a mistake on their mail-in ballot to request a new one. Instead, their only option will be to go to the polls on Election Day and cast a provisional ballot.