Delegating Outlook Calendar Permissions
The following steps are to grant someone permissions to view or edit Outlook calendars.
Step 1: Open “Sharing Permission” menu on the Outlook Calendar
Right click the Outlook calendar you want to share to others. Select “Sharing Permissions”.
Step 2: Select permissions and delegate the user
After that "Calendar Properties" menu will open. Click on "Add" then specify the person who needs access. Enter in the user’s email address at the bottom text bar or use the search feature to find the user. Once the email is entered you should click "OK".
Step 3: Verify permissions being authorized to user
You should see the following options after adding a user in. You can specify the level of permission that the user will have on the calendar. Edit allows the user to edit calendar events in the calendar. Delegate allows the user to receive meeting responses and requests on your behalf. After picking the desired permission level you will click "Apply" then "OK".
Step 4: Verifying the user received the invite
Once you complete your configuration, the user should receive an email showing that they have been invited to edit your calendar. The user will just have to click the accept button and the calendar will show up in Outlook.