When we send any file to print it is giving load manual feeder error

From Canon Help Files.

Automatic Print Head alignment failed
Possible causes are as follows:
A4 or Letter-sized paper is not loaded on the Auto Sheet Feeder.
Press the RESUME/CANCEL button on the printer to clear the error, then load one sheet of A4 or Letter-sized paper in the Auto Sheet Feeder.
Automatic print head alignment cannot be performed using paper from the Cassette. For automatic print head alignment, always load paper in the Auto Sheet Feeder.

Print Head nozzles are clogged.
Press the RESUME/CANCEL button on the printer to clear the error, and then print out the nozzle check pattern to examine the print head condition.

For information on how to print a nozzle check pattern, see "Printing the Nozzle Check Pattern."

The Paper Output Slot has been exposed to a strong light source preventing correct Print Head alignment.
Press the RESUME/CANCEL button to clear the error and move the printer to a darker location.
After carrying out the above measures, if the problem continues after aligning the Print Head again, press the RESUME/CANCEL button to clear the error, and then perform manual print head alignment. For details on manual print head alignment, see "Manual Print Head Alignment."

in the printer properties during printing change the "paper size" from letter to a4

You have send a print job from your application (ex. word), and the paper format in this appl. is letter. The printer tells you to insert a letter format paper in the mp (multi purpose) feeder (upper the tray).
If you press the GO key the print probably proceeds with print job (if has the paper load in mp feeder)

I received this message when I was trying to print a pdf file. I attempted messing with the positioning of green paper guide to no avail. My co-worker suggested I uncheck the Choose paper source by PDF page size box on the Print pop-up box. This did the trick.

You load the originals print side uo on the document feeder tray or print side down on the glass.
To send a single page fax you can either load the original on document feeder tray or on the glass; to send a multi-page fax you must use the document feeder tray.

The position of the paper is the same either you copy, fax or scan.
All this is clearly explained in the user's manual, that you should read and you can download from HP support pages for you printer:

Are trying to print to the MP feeder? If not, then you need to check whether or not is the selected paper source. Step 1: Go to the Printer's paper menu and scroll down until you see the Tray Select. Go into that menu and verify that the correct selection has been made. Step 2: Go to the "Printers and Faxes" Windows menu and then select your printer and verify the paper size and tray settings. Step 3: If you are using an application such as Word, go into page setup and verify that you have the correct setting. Last step, go into the driver, select "Print to File" and print the file. When prompted to name the file, name it mpfdr. Windows will append a .prn to the file name. Send the file to: [email protected]. I'll read it and see if I can fix it for you. Don

That is not an error message. it is telling you to load the Manual Paper feeder. Put some papaer in it and it will print. check youyr set up to make sure that you are printing to the trays not the manual feeder

Send a fax
You can send a fax in a variety of ways. Using the control panel, you can send a blackand-
white or color fax from your HP All-in-One. You can also send a fax manually
from an attached phone. This allows you to speak with the recipient before sending
the fax.
If you frequently send faxes to the same numbers, you can set up speed dial entries.
For more information on setting up speed dial entries, see Set up speed dialing.
Send a basic fax
You can easily send a single- or multiple-page black-and-white fax by using the
control panel, as described here. If you want to send a color or photo fax, see the
onscreen HP Image Zone Help.
Note If you need printed confirmation that your faxes were successfully sent,
enable fax confirmation before sending any faxes. For more information, see
Print fax confirmation reports.
Tip You can also send a fax manually from a phone or by using monitor
dialing. These features allow you to control the pace of your dialing. They are
also useful when you want to use a calling card to charge the call and you
need to respond to tone prompts while dialing. For more information, see Send
a fax manually from a phone or Send a fax using monitor dialing.
1. Load your originals, with the print side up, into the document feeder tray. If you
are sending a single-page fax, such as a photograph, you can also load your
original on the glass.
Note If you are sending a multiple-page fax, you must load the originals
in the document feeder tray. You cannot fax a multiple-page document
from the glass.
2. Press Fax.

Thanks mate, it worked for me too and my works printers (work in IT and this 'error' was driving us crazy)

Check the paper settings on your word processor. Most probably you picked either a paper type or paper size that is not plain, letter sized paper. That is why the word processor sends the job to the manual tray.