Fetterman was joined by U.S. Rep. Susan Wild in the campaign stop at Northampton Community College.
Acting Secretary of State Leigh Chapman says more than 5 million residents have used mail-in voting since 2020.
The vote will uphold the 2019 measure allowing any voter to use a mail-in ballot.
Activists are grateful to Gov. Tom Wolf for launching a suit that opposes proposed amendments to the state constitution.
Women’s ability to make their own decisions is a non-negotiable component to health care, Wild says.