Yes, runs 24/7. As for weekdays, a train can come every 5-10 minutes on peak time on all the lines. Saturdays and Sundays naturally are when ridership + demand would be lower, so a train would come every 20 minutes (Newark-WTC route) or 12 minutes (Journal Square-33rd St line). Unless if there’s any service modifications for that weekend, the only notable delay/change would be that trains would have a small wait at Journal Square for a few minutes extra due to track work in Kearny between Journal Square & Harrison stations. If you’d have to ride late at night (after 10PM) on weekends, trains can come usually every 25-40 minutes, so plan ahead.

If you’re new to this, PATH is kind of similar to the MTA in New York City across the Hudson River, and their trains go into lower Manhattan too, but for the most part it’s a lot cleaner/safer, and you’d rarely if ever get “interesting moments” like on the NYC subways. Bad thing is that since they’re two separate systems, for cases you’d want to take both (say going from WTC’s PATH to take the subway), you’d have to pay again.