Printer feeds more than one sheet at a time

Clean the pick up rollers with a soapy damp cloth.
Throw that paper away and put in paper from a new unopened pack. There is also an answer here.

Multiple Pages Feed through the Printer - HP Support

https://support.hp.com > ca-en > document
The printer picks up or feeds multiple sheets when printing.

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  Printer grabs multiple sheets of paper - HP Support Community

  https://h30434.www3.hp.com > td-p
  Sept 29, 2020 - This printer has no mechanism to keep the paper from sliding backwards and this was the problem. I have discovered that there is a whole opening at the bottom ...

it's sounds like something is getting loose as printer attempt to print, check all the door, are any of the door becomes loose as printer try to print ?
Vinay

A lot of people soon forget to "rifle" the paper before placing it into the bay. This helps prevent the paper from sticking during feeding. Just treat the paper like a book, and flip through the pages.

The first thing I would try is to clean the paper feed rollers:

1) Remove the paper and power on the printer
2) Press and hold the <Resume/Cancel> button until the power lamp flashes three (3) times, then release
3) Cleaning will start automatically
4) Wait approx. 30 seconds for cleaning to complete
5) When the power lamp lights, repeat #2 above

I suggest repeating #2 at least 5 times. Then you are ready to see if a single sheet of plain paper will feed.

1) Load a single 8.5 x 11 plain sheet of paper
2) Press and hold <Resume/Cancel> button until power lamp flashes three (3) times, then release
3) The paper should be picked up and fed through the printer.

You may wish to repeat this process as well (#1 and #2 above) to insure the paper is being picked up to your satisfaction.

Every 120,000 pages, the paper feed rollers, fuser, transfer roller, and OPC belt cartridge should be replaced, usually by a trained techncian.
Fuser and OPC belt units are customer-replacable.

The multiple feeding of the paper into the printer is due to a worn paper separation pad. part no. LM0711001. If the machine is picking up the paper okay and the jams occur solely from multiple sheet feeding, then this part is probably all you will need. The steps required to access and remove & replace the separation pad unfortunately is about 10 steps. Better consult a tech.

The paper feed solenoid is sticking, it can be seen thru a hole in the back with the door opened. Not easy to get to, but I have been able to bend the stop tab slightly and run just fine.

Was the printer feeding multiple sheets at the same time, so that the sheer thickness of the wad caused the jam? If so, look into the slot where you load paper (this is called the automatic sheet feeder or ASF). You should see a small roller with a rubber coating. This is what pulls the sheets into the printer. Put one sheet of paper into the ASF and do a print. The Windows test print facility is convenient for this: start-control panel-printer and faxes, then right click your printer icon and select properties, then test print). If this works OK, put two pages into the ASF, then three etc. Observe what happens. If at some point more than one page is pulled in, it infers that the ASF is not working properly, in which case you will need to consult a technician (or have a go yourself at dismantling the printer). If the one-two-three-four etc page test doesn't produce a multiple feed, all it probably means, is that static electricity is holding the sheets tightly together. Make sure when you put a wad of paper into the ASF it has been fanned.

Report back on what you find, or if you have any queries on the above.

Most faxes have a rubber separation pad which is designed to stop multi feeding. It is in the feed area.
They vary in size  but can be up to an inch square.
If they get dirty they can slip and allow more than one page to feed, if this happens you can clean it with a damp rag with a bit of detergent on it . If this does not work (give it three or four tries) you will have to replace the separation pad 

without some information about the kind of printer and the weight/thickness of the paper, try to supply more information in a comment if you can, this is a generic answer.
many printers have a paper thickness adjustment that helps ensure that only one sheet is picked up at a time, and that the sheet feeds accurately,
if two or more sheets are picked up there are jams as multiple sheets do not feed well, and may not even get out of the paper tray. If the printer is set for a thicker paper, the lead edge of thinner sheets may miss its aimed path and wrap around guides or rollers, jamming.
The makers web page, or the user guide if you still have it, often have FAQ on paper jams,

The most likely culprit is that the rollers that pull the paper are dirty. Use the steps below to clean the rollers.

If paper does not feed correctly, perform the following to clean the paper feed rollers:
1) Confirm that the printer is powered on.
2) Remove any paper from the printer.
3) Press and hold the <Resume/Cancel> button.
4) Release the <Resume/Cancel> button after the Power lamp blinks three times.

Note: The Power lamp will blink and the paper feed roller starts cleaning itself by revolving.
5) When the Power lamp lights in green, repeat Steps 3 and 4 up to two additional times. (Please wait approx. 30 seconds for paper feed roller cleaning to complete.)
6) To confirm whether cleaning has been performed properly, set a blank sheet of plain paper (8 1/2 x 11 Letter size) in the sheet feeder or cassette.
7) Press and hold the <Resume/Cancel> button and release it when the Power lamp blinks three times. (The paper set in the printer is picked up and fed.)
8) Repeat the process as necessary