Open AI // Postman // Form (?)

Hi there,
I am new to API calls, and working my way with Postman, and trying to solve something and stuck - would really appreciate some help.
I managed to do an API call in Postman for ChatGPT, with “Raw” selected in the body. It looks like this:
“model”: “text-davinci-003”,
“prompt”: “Albert Einstein was”

So far so good.

Now, I am working with Wized in Webflow, and I am trying to fit to the forms there - and do the same request, but for that I need this to work in the “Form” version - meaning, a request that looks like this:

key: model text-davinci-003
key: prompt Albert Einstein was

And I am getting a result saying:
“error”: {
“message”: “you must provide a model parameter”,
“type”: “invalid_request_error”,
“param”: null,
“code”: null

I have to make this work with a form, so I can have these solutions for Wized in Webflow. See image here:

Any idea?!?