First, add Planner App to Teams Channel. Click plus button

Select Planner App and specify Tab Name

Click Save

Planner appears as a tab in Team Channel. Find an existing template and open up the flow (Dynamics Activities to Planner Tasks)

Integration of Microsoft Teams with Dynamics 365 - Dynamics Activities to Planner Tasks

Select and click Continue. Now we need to customize existing connectors and actions. (Remember that you need to reset all fields in this flow with your organizations' attributes even if they are filled, otherwise, the flow will not run successfully). Select Organization Name.

Select Task from the list as a primary entity. Get record and define Item Identifier as a Task

Enter the email to specify a valid Office 365 user in the Get user profile connector. Specify parameters as needed for the Planner connectors.

Plan Id - select Task Bucket Id - select To Do Start Date - reset Start Date Due Date - reset Due Date Assigned User Ids - set Mail

The same for no assignment - leave Assigned User Ids empty. Click Save and Test.

Select - I’ll perform the trigger action. Click Save and Test.

Navigate to Dynamics. Create a new Task and navigate to Run History of the flowYou can try another way and add tasks directly from Teams using the Dynamics record tab. Click plus ‘button’ on Timeline and select Task.

Specify all parameters as needed and click ‘Save’

You have created a new task for this Account. It might take a few minutes for the flow to get applied. Navigate to Flow and check Run History. A new item has appeared. Return to Teams Planner - a new task has been automatically created as well.