Yes, Office 365 and Microsoft 365 are essentially the same thing in the context of the Fundamentals Certification. Microsoft rebranded Office 365 to Microsoft 365 a few years ago.
The Microsoft 365 Fundamentals Certification focuses on foundational knowledge of cloud-based services:
Cloud Concepts, Microsoft 365 Apps and Services, Security, Compliance, Privacy, and Trust, Microsoft 365 Pricing, Licensing, and Support.