TypeIt is a high quality jQuery plugin that types text a given string or strings of text on a page. Its responsive, lightweight and easy to customize.
To get started you can either pass in settings object, use data-typeit-* attributes, or You can define your string by dropping it directly in the HTML element. You can have it play back multiple strings and even set it to delete the previous string before starting a new one for that realistic effect. You can also alter details like speed, and even pacing to make it feel like a person is doing the typing.