Save a web page to iBooks
When you tap the Share icon in Safari, you can save the current page to iBooks as a PDF. This won’t necessarily preserve the page’s formatting. If you want that and don’t care about keeping pages around in the long term, it’s still better to add them to Reading List, which stores a copy for reading offline. Don’t be put off saving a page as a PDF. It’s not as accurate as Safari on the Mac’s option of saving a proper archive, but view a page in Safari Reader (using the paragraph icon in the Smart Search field) then save that view as a PDF and you’ll get a nicer looking document.