I recommend using typed.js or typer.js for creating this typed field. Because all you need to do is add some js to your site (just a reference link) and then give some text a span tag or a class and then it'll type out whatever you have in your reference and will inherit your class styling which you give some dummy text in the design view.
Here it is in a codepen: http://codepen.io/drocarmo/pen/rsjzp
Here you can download the source files to host on a server: http://www.mattboldt.com/demos/typed-js/
Here's another codepen: http://codepen.io/jasondavis/full/fHdAt/
This way you don't have to use an embed code. You just add this to your header:
strings: ["Type anything here to that you'd like it to type out for you", "If you type something here, then it'll get deleted and type this second set of text."],
Then create a div or paragraph with placeholder text, give it the class which says "elementnamegoeshere" or whatever you'd like to name it (keep in mind that it is case sensitive) and publish the page. You can style the text to have whatever look or feel you'd like.
Please let me know if you have any questions
EDIT: Changed the post to "Embed/Custom Code"