The best choice depends on the specific needs and preferences of your organization.
Any guests added to Microsoft Teams or Azure Active Directory are also added to the list of guest users in the Microsoft 365 admin center. Guests can join meetings, view documents, and chat in Teams to which they are invited.
If you need to collaborate with guests in documents, tasks, and conversations, we recommend using Microsoft Teams. Teams provides all the collaboration features of Office and SharePoint in a unified user experience, including persistent chat and a suite of customizable and extensible collaboration tools.
Alternatively, they can add you as a guest user in their Azure Active Directory. This will give you access to all the resources and apps that they have made available to guest users in their tenant. However, this method may require more setup and configuration on the organization's part.
If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.