As far as a leave application system goes. There's many more other features can be added beside those that's in the object. Sample upload evidence, assign group to different supervisor or manager and many more.
Knowledge required for the system will be PHP, MySQL and Javascript. Typically, this project has a lot potential area to add or enhance.
Objective
1. Enhance the feature in the system to cater for emergency leave, half day and pregnancy leave and etc.
2. Add remarks for supervisor or manager when approving leave.