Q: Can I plug a USB external drive into my ipad3?

No

Only if you have an app for those documents on your iPad.

For more information on this read http://www.macworld.com/article/1151397/word_ipad.html

Allan

You can use a USB flash drive & the camera connection kit.

Plug the USB flash drive (works the same with an SD card) into your computer & create a new folder titled DCIM. Then put your movie/photo files into the folder. The files must have a filename with exactly 8 characters long (no spaces) plus the file extension (i.e., my-movie.mov; DSCN0164.jpg).

Now plug the flash drive into the iPad using the camera connection kit. Open the Photos app, the movie/photo files should appear & you can import. (You can not export using the camera connection kit.)

Using The iPad Camera Connection Kit

http://support.apple.com/kb/HT4101

Secrets of the iPad Camera Connection Kit

http://howto.cnet.com/8301-11310_39-57401068-285/secrets-of-the-ipad-camera-conn ection-kit/

 Cheers, Tom 

Hello you would need to have Pages for iOS on the iPad if you are referring to 'iCloud' you can download and edit some office documents but beware always create a copy of original for editing purposes as some formatting options are not the same. With The iWork Suite for iOS  (free on all iOS Devices sold by Apple or auth resellers after 10.22.2012) You will be able to work with and manage many of your office documents)

http://support.apple.com/kb/HT4942

At this time MS Office is not available for any iOS device.

You can use apps such as Drop Box or Google Drive (may also be called GoDocs) to have non editable copies of all your documents available between pc and iPad.

Also here is an answer found in the Apple Online store Q&A

Best Answer

There are several office apps on the iPad like Apple's iWork, QuickOffice, DocstoGo. They cost between $10 - $20. There are some free apps too but dont have the editing features of a MS Office suite and mostly don't open MS office documents properly. Also I found them very difficult to use on the iPad. AstralPad is the best Office app in terms of editing features, It is definitely worth trying and it is FREE.

Answered by Mita S from St Davids Jun 6, 2013

Does that work if the files are neither photos or movies ?  In other words, for the .docx files the OP is asking about ?