Assuming that you:
- include Annual Leave as an option in the Absence Requests form, and
- you have an Absence quota (e.g. 20 days per year), and
- you would like to exclude public holidays/institutional closure days from this quota
You can add institutional closure dates in Reports → Edit institutional closure dates. When added, Annual Leave requests in GEM will take these dates into consideration (e.g. not count a public holiday towards the Absence quota):