If you expect like chat bots means,
1. Create a Form
2. Place the TextArea for User input
3. Place the buttton for Submit
Whenever the user enters the input and clicks submit, get the content of text area analyze the string and update the text area with new line.
Take a look at old style UI of ICQ or AOL (google search in pictures).
Not so easy but: you can create any ui using html and JS. And using weblink to interact with toolkit (backend) apps. Maybe even possible to integrate some web chat or web assistents solutions in this maner...
Update the user input into Text area when submit