The deadline to register to vote in Pennsylvania’s primary election this year is April 16.
You can easily register online at https://www.pavoterservices.pa.gov/Pages/VoterRegistrationApplication.aspx
If you prefer to mail in your registration, it must be postmarked no later than April 16.
A note about the signature requirement for online applications from http://www.votespa.com:
Q: Do I have to sign my voter registration application?
A: Pennsylvania law permits the use of electronic signatures in all transactions where a handwritten signature may be used. Applicants using online voter registration will be required to affirm that they are qualified voters and may sign their application electronically.
However, your voter registration is not complete until your county voter registration office has your written signature on file. If you have a Pennsylvania driver’s license or PennDOT ID card, your signature on file at PennDOT will be sent to your county voter registration office and attached to your voter record. Applicants who do not provide a PennDOT number or whose information cannot be verified at PennDOT may upload a digital image of their signature, or submit their signature by mail or in person to complete the registration process. Your signed application must either be delivered to your county voter registration office or postmarked no later than the registration deadline.