Anyone in PA who hasn't turned in their mail in ballot should not mail it at this point. Drop it off at your county election office or at a drop box. If you want to vote early in person, you can either visit your county election or a satellite office.
Most states have secure dropbox locations for your mail-in ballot. For no particular reason, here is where you can find a dropbox in: PENNSYLVANIA:
I highly recommend this method of voting. I did it Sunday, and received an email confirmation that my ballot had been received. It only takes a few minutes and is safer than going to the store. Here's the website where you can find where drop off yours