Step one: Head to your calendar
In your Outlook inbox, click on the calendar in the bottom left corner of the screen.
Step two: Choose the calendar you want to share
On the toolbar at the top of the screen click on “Share Calendar” (it’s a rounded triangle with three circles at its points).
On the dropdown, decide which calendar you want to share. People with multiple calendars will see all that can be shared here. When you choose the one you want to share click “Add..”.
A new box will appear. From here, pick the people you want to share your calendar with. Click on the name and then “Add” at the bottom left. Once you’ve made all your selections, click “OK”.
Everyone you’ve added will appear with the default permission level. You can change this.