Citizen Printer

I have a hp deskjet printer I have a problem?

I have a hp deskjet printer I have a problem although there is no paper in it its showing paperjam whats a problem in it?

Maybe the sensor for paper level is dirty, or where the paper tray is has something blocking one of the sensors. See if you can see any paper/dirt inside the system, try blowing things out with some canned air and trying it again, make sure to unplug it first.
You might have a small paper or something near the sensor check it and clear it with your vaccum cleaner