Que? What is a form? Do you mean a Glide Page? Tried using those and they don’t make sense. Doesn’t load any columns.
Have already set up an app working properly, just need to stop it providing access to anything but an ADD form.
Create a tab with a details style layout in your app.
Place a form button on it and nothing else. Users can click on the form button to submit their application to the Google sheet that you want to receive the data. Nothing will be displayed on the screen except for the form button and the form itself.
I would recommend applying row owners to the sheet that’s receiving the data to securely protect the data as well.