Technically you would be federating your Office 365 tenant with your Okta org. After you've done this Office 365 would actually be performing authentication against Okta. Once this is in place the process of configuring similar SSO (and in some cases account provisioning) to other SaaS solutions would be a trivial matter.
Are you currently using Okta?
Do you have an on premise directory you are working with? (Active Directory)
Original Author: Matt Egan, Varian Medical Systems