HR users can define new days that will not count to used days when creating new Vacation Document. Every new created holiday can be defined as one time only or yearly, or in case of workdays - days of week week.
You can access this panel as HR User from Navigation Bar Menu ➜ Management (1) ➜ Holidays (2). To add a new vacation, please user "Add vacation" button.
Please be advised - users won't be visible here if they are not members of "Users" of a particular team. Fore more information please check here.