Adding an ICS Feed (Subscribed Calendar) to Office 365

1. Go to https://portal.office.com/calendar
2. Press Add Calendar at the top left
3. Select From Internet
4. In the Internet Calendar area of the pop-up paste the URL
5. Give the calendar any name you like in the Calendar name field
6. Then press Save

Where can I find URL?

1. Log in to our website
2. Select Account at the top right
3. Scroll down a bit, URL starts with webcal://

This should work, provided your Administrator allowed calendar publishing