Using IOS with Offline Data (importing files)

There is an called File Manager that is designed for both cloud services connections and local file storage. It works with iCloud, DropBox, Google Drive and Box, as well FTP servers.

File Manager will handle multiple downloads to the local storage

Readdle's Documents does as well.

GoodReader can do this, too.

Note that as per the operating model that iOS uses, there is no "filesystem" visible to the user (i.e., the C: drive) and each app has a private area where its documents are kept. Means you have to explicitly Share them with any other app capable of using them (for example, Mail, iBooks and Adobe Acrobat can all handle .pdf files, with different functionality).

That being said and beyond the use of Dropbox, Google Drive, MS OneDrive, etc., you can also upload, download and manage files on a per-app basis with a computer that's running iTunes and has the device registered to it. Once plugged in and in the device's window, select Apps on the left column and scroll down past the screen layouts section to File Sharing. Select an app from the left column and see its files on the right. There are buttons to Add… (from computer to device) or Copy (from device to computer). And you can erase with the Delete key on the keyboard.

I'm carrying over 2GB in PDF manuals and such in Adobe Acrobat DC and over 9GB in an extensive iBooks bookshelf, all perfectly readable way out in the boondocks where no connectivity is to be found.

Why bother with just a READER, when you can have the whole enchilada? Install the full, real, official MS Office (Word, Excel, PowerPoint, and OneDrive which works like DropBox), activate for free home use with your Hotmail account, and do all those docs freely between your mobile and your regular computer. OneDrive ties all together seamlessly.

As for moving files around, look for the Share icon: a square with an arrow coming out the top. Tapping on it you'll see two rows, other apps you can send the file to or activities you can do with it (like Print). If what you need isn't there, scroll the row to the extreme right to the More icon ( ... ), tap on it and see what you can activate.

Enjoy...

Edit: In iBooks, visit the iBookstore, go to the Free Books / Computer & Tech section and download the full iPad User Manual (and/or the iPhone) to carry around for offline use. Cause I'm gathering you haven't read it yet...

Dropbox works fine in offline mode. Dropbox syncs files between the cloud and ios. Once the files has been synced, it's on the ios device. Turn on airline mode, to see what is really on your device.

GoodReader

-- With GoodReader on your iPad/iPhone, you can read virtually anything, anywhere: books, movies, maps, pictures.

-- sync with Dropbox, OneDrive, SugarSync and any WebDAV, AFP, SMB, FTP or SFTP server

-- The types of annotations that can be created and edited in GoodReader include typewriter text boxes, popup comments ("sticky notes"), text highlights, freehand drawings, lines, arrows, rectangles, ovals, cloudy shapes, text underlines, strikeouts, text insertion marks.

http://www.goodiware.com/

PDF Expert – the PDF handling app for the iPad. "It allows you to markup documents with highlights and handwriting, insert text and stamps, sign and even merge PDFs."

https://itunes.apple.com/us/app/pdf-expert-5-fill-forms-annotate/id743974925?mt= 8

iAnnotate – turns your tablet into a world-class productivity tool for reading, marking up, and sharing PDFs, Word documents, PowerPoint files, and images. Has a secure document edition designed for corporations.

http://www.branchfire.com/iannotate

Great!

Good old FTP

FileApp and FileApp Pro

I use Mac OS pureFTP server. It comes as part of PureFTPd Manager software download at this site.

http://www.macupdate.com/info.php/id/12630