One of my favourite apps is Pocket for iOS and android.  As you can see, I feature in the top 5% users of usage.

Pocket allows a neat way to save web articles, links or videos into its app which you can read later.  It also syncs across phones, tablets, computers and more. It is truly cross platform.

You can save stuff into Pocket directly from many apps and services. In iOS you have a share sheet extension. You can also listen to your saved articles with Text-to-Speech.

Another option for saving web pages is using Dropbox on iOS.Whilst using Safari, if you save to Dropbox using the share sheet option, it saves the entire page as is, and as a PDF which you can view later. 

Link for iOS version – Pocket in Apple App Store

Link for android version – Pocket on Google Play Store