Is done using a js script - Typer.js – I’ve used it myself in the past and it works great. https://cosmos.layervault.com/typer-js.html It does require that you have some experience with using javascript and custom code…
Follow the steps in the link above - you’ll need a place to host the jquery script and files. And call the script by using the custom attributes section in webflow on the text you want to animate: