You can use the Outlook for the web to publish your calendar so that others outside of your organization can see when you are busy. Create URLs that will allow people outside your organization to view your calendar online. One URL lets the recipient subscribe to your calendar by using Outlook or Outlook for the web, and the other lets the recipient view your calendar in a web browser. You can control how much detail others can see. To share your calendar with users inside your organization follow the instructions located here: https://support.office.com/en-US/article/Video-Share-your-Office-365-calendar-9C68F21A-8824-4ABB-BEA7-DEE64DC33E15. To share your calendar with users outside of your organization follow the instructions located here: https://support.office.com/en-us/article/Video-Publish-your-Office-365-calendar-or-send-it-in-email-856afe2b-dda3-49ed-87b3-df6ff515002a.