How Can One Create A Shared Calendar On Microsoft Outlook By The Whole Office?

If you have a Microsoft Exchange environment, this can be done in Public Folders, check with your Systems Administrator or ask here.
In a non-Exchange environment, there is no native method in Outlook to share disparate installations' calendars, and you will need a third-party tool to assist in the task, but there will a cost impact to achieve this.
As an alternative, try using shared Google calendar(s), which is my own preference...