Trick for saving web document on iPhone (especially long ones to read later)

You can turn web pages into PDFs and add them directly to your iBooks app. This is handy if you’re reading a long web document, or especially if you’ve found a HTML book online and want to keep a copy of it.

When you tap Share, scroll across the apps to find Save PDF to iBooks. Tap it and the web page will be converted and added to your book collection.