Hi @Wang
There is no direct and effective method in sharepoint online to add holidays automatically.
- As a workaround, you could sync the calendar list to Outlook:
2.Then add holidays to your calendar in Outlook for Windows
3.After you add all the holidays to your Outlook calendar, open up the SharePoint Calendar in Outlook - Drag and Drop the events from Outlook to the SharePoint Calendar in Outlook.
Holidays added to SharePoint Group Calendar through Outlook will be synced immediately.
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