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If the paper was loaded for scanning or copying, in the ADF Feeder, then one method of clearing the jams, is done.
If it was loaded in the front tray, then the jam must be cleared from the back, by removing the two-sided unit. Press and hold the tabs on left and right, and pull out the unit. Then remove the paper from the interior and/or from the unit.
Trying to clear jams from the front can damage mechanisms in this sort of HP printer (like some other HP printers also.) Have you tried doing that already? I hope not.