Event details
Can someone who's not in your tenant interact with tasks that you assign?
TarkanSevilmisMicrosoft
You can add people from outside of your tenant and guest users and assign tasks to them. They will be able to work with the task as regular users. There is additional information here: https://support.microsoft.com/en-us/office/guest-access-in-microsoft-planner-cc5d7f96-dced-4da4-ab62-08c72d9759c6