The holidays in a particular year can be added under the Holidays list. The importance of adding holidays is, your SLA (Service Level Agreement) wont be breached in case an incident comes on a Holiday.

Admin Setting >>Automation  >> Holidays

Mass Action on Holidays:

It is possible to select either of the Holiday or more than one Holidays with the help of checklist and perform the desired action on them. The status of the Holidays can be either enabled or disabled.

Add Holidays:

Additional Holidays can be added using the Add option. When you click on Add you will have the following

fields:

Date: The date and the month of the particular holiday should be specified here.

Description: The description for the particular holiday should be specified here

Status: It is possible to enable or disable the particular holiday.

Update Holiday: It is possible to edit or update a particular holiday by selecting it from the listing. 

The changes can be made and it can be updated by the Update option present at the bottom.