The Microsoft Graph API is just another, extremely useful API, that can be used in variety of automations within the whole Microsoft 365 ecosystem. I am quite often using it with Logic Apps processes, that are running on application permissions.
On 21st August 2019 Microsoft announced that actions in Microsoft Flow from Outlook stack, are going to be moved from using Outlook REST API v1.0 to Microsoft Graph v1.0. Along with that information there was also written, that current Outlook API 1.0 is going to be decommissioned in 1st of November 2019. So after that date all old actions in Microsoft Flow are going to be removed too.
This may seem trivial, but if you want to create a Flow, that is parameterized, where a name of a group and list of members is passed as the request parameters then it turns out it is not that straightforward.
In Microsoft Flow there is a set of actions, that allow to work with Office 365 Groups. There is also one dedicated to adding new members (only “Members”. There is no way currently to add “Owners”).