how to check when the employee must go for vacation or not or how many days of vacation he has and so on.
can someone help please
Have you checked Holiday List ?
yes but maybe i am wrong,
on holiday list, i put there the day off for the all employees and so on,
or its update but its selves once the person works?
If you have selected a holiday list in the Employment Details form, the system will give priority to the form mentioned here. It will fetch the list mentioned in the form rather than the one which you may have specified as Default; However, if there is no list in the employment details form, the default list will be fetched.
https://frappe.github.io/erpnext/user/manual/en/human-resources/holiday-list
Hope this helps.