Hi @RachidL,
congratulations on your first question in the community!
I understand what you mean! I think the attribute type is set as a text field by default, to allow for more flexibility. For example when applicants need to write a comment like “End of January” or something like ” notice period of 3 months”, in case they haven’t quit their current job yet. In those cases, a date attribute would be too restrictive for the applicant.
As you already said, there is no possibility to change that, as it is a system attribute. What you can do is to hide the attribute from the application form. You can do this in the career page settings (Settings > Recruiting > Career Page > Application form settings).
For more details, take a look at this Help Center article: Configuring the Personio Career Page
If there are any open questions, I am here to help!
Best wishes
Marc