Vendor field in product creation

Hello,
I have a site under construction with Hikamarket.
I used this site to create a second site (copy / paste).

On the second site, when I create a product, I can choose to which seller I assign it, via a field in the product creation details.

However, on the first site, I don't see this field. Instead, I have a quantity field. I don't understand why. I had to change something but I can't find what.

Hi,
Here is a screenshot, do you talk about this plugin ?
If yes, it is published. Hikamarket is installed and configured.
I can go the admin or frontend menus without problems.