I recently downloaded the Kindle app to my Ipad and personal computers so that I can read library books downloaded from Overdrive on them. I wanted some experience with them so I'd be familiar with the app and what it can do to share with library people I work with.
I was pleased with the ease of use. If you have multiple devices in your "Manage Your Kindle" account, you can specify which device you want to send the downloaded e-books to.
I was even more pleased to learn about the Send to Kindle for PC app that Amazon recently introduced. You install the app on your PC and can use it to send any document to your Kindle. If sent using the print function, the document is sent in a pdf format to the cloud storage where you can again manage which device you want to send the document to. I experimented and was able to send documents easily not only to a Kindle Fire but also to my Ipad which has the Kindle app installed on it. The beauty of the Kindle app for Ipad is that it simplifies reading pdf files on the Ipad, which has no native ability to handle pdfs.
To send personal documents you can do either one of these:
From Windows Explorer, simply right click on one or more documents and choose Send to Kindle. To send multiple documents to Kindle without opening them, simply select documents and choose Send to Kindle from the right-click menu in Windows Explorer
Or, from any Windows application that can print, select Print and choose Send to Kindle (documents are delivered in PDF format).
Send to Kindle is supported on Kindle Library on Kindle Keyboard (with the latest software update, version 3.3), Kindle, Kindle Touch, and Kindle for iPad, iPhone and iPod touch (running Kindle app version 2.9 or greater). Kindle Personal Documents Service is currently not supported on other free Kindle Reading Applications, although a Mac version is said to be coming.
In addition, you and your approved contacts can send personal documents to your registered Kindle devices, supported Kindle reading applications, and your Kindle Library in the Amazon Cloud by e-mailing them to your Send-to-Kindle e-mail address ([name]@kindle.com)as well. Your Send-to-Kindle e-mail address is a unique e-mail address assigned to your Kindle device or supported Kindle reading application upon registration. To have a document converted to Kindle format (.azw), the subject line should be "convert" when e-mailing a personal document to your Send-to-Kindle address. Converting the document enables you to use functionality like like variable font size and annotations.
You can find more information about the Amazon Kindle Personal Documents service here.