Hi Roberto,
Thanks for your post.
Any string or label in the application can be modified with a translation file to be whatever you want it to be.
Although a translation file is traditionally used to change the language of a plugin, it also will change ANY string or label in the plugin (For example, you can change the word "Search" to "Find") We have full instructions on how to do that here: https://awpcp.com/quick-start-guide/#qs-translate;awpcptrans
If you want some of the original form fields to not show on the ads, you can control that under Classifieds > Settings > Form and unchecking the fields that you don't want.
Please try that and let me know if you run into more issues.