How to read these

Which one should I take?

EPUB, almost always. It reflows to your screen, so you can change the type size and the text still fits. It is what Kindle, Kobo, Apple Books and Google Play Books all want.

PDF is a fixed page — it looks identical everywhere and prints properly, but on a phone you will be pinching and scrolling. Take the PDF if you want to print it, or if you are reading on a laptop.

Kindle

Modern Kindles read EPUB directly. The easiest route is email:

1. Download the EPUB to your phone or computer.
2. Find your Send-to-Kindle address in Amazon under Account → Content & Devices → Preferences → Personal Document Settings. It looks like yourname@kindle.com.
3. In that same settings page, add the address you will send from to your Approved Personal Document E-mail List. Amazon silently drops mail from anywhere else.
4. Email the EPUB to your Kindle address, with the file attached. Subject line can be empty.
5. It appears on the Kindle within a few minutes over Wi-Fi.

Alternatively: amazon.com/sendtokindle lets you drag the file into a browser window, or plug the Kindle in by USB and drop the EPUB into the documents folder.

Kobo

Plug the Kobo into a computer with its cable, open it like a USB drive, and copy the EPUB anywhere on it. Eject, and it will be on your home screen. Kobo handles EPUB natively.

iPhone or iPad

Tap the EPUB download and choose Open in Books. That is the whole procedure. If Safari saves it to Files instead, tap the file there and share it to Books.

Android

Install a reader — Google Play Books, Moon+ Reader and Librera all work — then open the downloaded EPUB from your Downloads folder and pick the reader when prompted.

Computer

Calibre is free, cross-platform, and will also convert between formats if you need something exotic. Apple Books on a Mac and Microsoft Edge on Windows both open EPUBs without any install.