How to use iOS 11’s password autofill for apps
iOS 11 extends Safari’s password autofill out of the browser and inside apps. In iOS 11, when you download a new app — a Twitter app, say, or an email client — then you won’t have to visit your password manager of choice, then copy and paste a username and password between apps. Instead, if you already let Safari save the password in the browser, it will automatically filled in in the app, too.
(via Cult of Mac – Tech and culture through an Apple lens)