Not quite following what you’re trying to do here.
Are you talking about making a “user” post type similar to perhaps an “employees” section where you highlight a company’s employees and each post is perhaps their name, and then you add a biography and perhaps roles/duties, and an employee photo? Or something similar?
I will try to be as clear as possible
I use the gravityform application is a plugin which makes forms very advanced. On the other hand, this form uses a lot of functionality from wordpress
I will try to provide you with as many images as possible for my questioning.
So I create a form that looks like this to try the dropdown functionality
https://prnt.sc/LqDNlJ7JdzCn
https://prnt.sc/6O_C07Ogem6p
the only problem is that when I use a post type I can’t see the authors or the users I would like to create a dropdown with all the users of the website. To facilitate the use of the form. I was advised to use your plugins to add a standard post, however I can’t get users to be added as information.
I will give you two examples
example 1 : I can’t get a selection
https://prnt.sc/ZBU2W3SnIk1i
https://prnt.sc/PFjye2JE1UMw
example 2 : You will notice with the second that I have a selection with the second post type
https://prnt.sc/UXaJP5LrH8_a
https://prnt.sc/dftwtMM2d3f2
This will allow me to have a list of uses directly on the web page in a form instead of having it in the wp-admin. I hope I have provided as much information as possible.
I forgot to mention the author that you find in the list comes from your extension
Alright, here’s how I’m reading things this time around.
You have a post type named auteurs, and you have posts in that post type.
You also have a form that’s meant to integrate with that post type, first by selecting the auteurs post type itself, and then a second dropdown that lets you select the posts themselves. Once saved, the form, when submitted to, does something with that chosen post.
However, the dropdown used to choose the posts, is not being populated?
Best guess I have for that is that show_in_rest is set to false. Beyond that, I feel like it’d probably be a better question for Gravity Forms support, since they’re the ones creating the UI for those dropdowns in the screenshots.
for this function I am in French you have a photo to help me 🙂
If you’re referring to the “show_in_rest” part that I mentioned, that’s part of our UI, as shown here:

One of the dropdowns when registering the post type. We default it to true, so you would have had to intentionally set it to false with the post type when saving.
hmmm..
it is of course true and this does not seem to matter
At this point, I’d be checking with GravityForms support since they’re the ones creating that UI.
CPTUI itself is only registering the content types to be available, but we don’t dictate how they’re used.