You can allow other exchange users to view or edit your Outlook folders by the Delegate Access feature in Outlook, including the default calendar folder.

1. Click File > Info > Account Settings > Delegate Access.

2. In the opening Delegates dialog box, please click the Add button.

3. Now the Add Users dialog box comes out. Please add the exchange users who you will allow to view or edit the default calendar items to the Add box, and click the OK button. See screenshot:

4. Now you get into the Delegate Permissions dialog box, please specify one of permission levels from the Calendar drop down list, select None from other drop down lists, and click the OK buttons successively to close both dialog boxes.

Notes:
(1) If you want to allow other exchange users to view your calendar items only, please select Reviewer from the drop down list; to edit your calendar items, please select Author or Editor from the drop down list.
(2) If you want to prevent other exchange users from viewing private items in the default calendar, please uncheck the Delegate can see my private items option. See screenshot above:
(3) Delegates can open and view your calendar folder easily with this method.

Automatically forward every email to the specified recipient in Outlook

Generally speaking, we can set a rule to automatically forward emails to the specified recipients, such as your another email account, your Gmail, or your colleagues, etc. But, all we know it will take a long time to configure a custom rule in Outlook. Now, we introduce Kutools for Outlook's (Automatic) Forward feature, which can set a auto forwarding rule with several clicks only.

Let’s say you want to allow other exchange users to view or edit one calendar which you created manually, you can change this calendar’s properties to achieve it.

1. In the Calendar view, select the calendar which you will allow other exchange users to view or edit on the Navigation Pane, and click Folder > Calendar Permissions. See screenshot:

2. In the Calendar Properties dialog box, click the Add button.

3. Now the Add Users dialog box comes out, add the exchange user who you will allow to view or edit your calendar into the Add box, and click the OK button.

4. Keep the new user selected in the above box, and then select one of permission level from the Permission Level drop down list, and click the OK button. See screenshot:

Notes:
(1) If you want to allow other exchange users to view this calendar, please select Free/Busy time, Free/Busy time, subject, location, or Reviewer from the Permission Level drop down list; to edit this calendar, please select Author, Editor, or others from the drop down list.
(2) You can also set a custom delegate permission with checking options in the Read, Delete Items, Write, and Other sections as you need.

Delegate access permissions for other Exchange users in Outlook

Ask for accessing other’s calendar permission in Outlook

Set permission for viewing Free/Busy information in Outlook