To register to vote online:

https://www.pavoterservices.state.pa.us/Pages/VoterRegistrationApplication.aspx

To download and print a voter registration form:

https://www.lehighcounty.org/Portals/0/PDF/Voter/OnlineVoterRegFormBlank.pdf

Your form must be mailed to:

Voter Registration
Lehigh County Government Center
17 S. 7th St.
Allentown, PA 18101-2401