In Safari on iOS 12 there is a protection against fraudulent keyboards
Apple is constantly improving the Safari browser, adding new features to improve security. In iOS 12 Safari is able to find and block fraudulent on-screen keyboard.
This is a function that users don’t notice, but it is constantly running and cannot be turned off. Safari all the time analyzes sites for on-screen keyboards, which collect data about users, including usernames, passwords and Bank details. If you notice a suspicious site, it will show a warning.
Found a new function of one Reddit user. To display the alert, you must open any website, for example, YouTube in full screen mode, and then enter the text in the bottom of the screen, like on the keyboard. Repeat this trick is difficult, but possible.
Of course, YouTube is an authoritative site, so you can trust him. But the developers, this feature will be useful to suspicious websites that may steal the data.