In Dynamics 365 for Talent you can set up leave and absence plans that employees be added to, so that they can register time off.
You can set up the plans as you want, to get a Talent with leave and absence plans suited for your company.
As HR you can se information about each employee and how much time they have available and how much time they have taken.
A manager gets full overview of their employees leave and absence in the manager portal
You can see some analytics about leave and absence.
The employees can register absence and apply for leave on their self service portal.