Account admins can specify non-working days for the entire account. For admins on Enterprise accounts, this right may be revoked.
You can create account-wide calendar exceptions that denote public holidays or your company-specific non-working days. These exceptions become visible in all users' personal work schedules and in tasks' nd projects' date pickers.
It's also possible to add additional working days for all users in the account using this manual.
Click your profile image in the workspace's upper-right corner.
Select Settings from the dropdown.
Click Work Schedules in the left panel 1.
Scroll down to the calendar and select a range of dates. Or double-click on a date to create a single-day exception 2.
Select a calendar exception type: Additional workdays, Public holidays, or Other non-working 3.