Follow the next steps to share a task with Planner on your team:
1. Add a Planner tab to your team channel
2. In your team channel, select Add a tab +.
3. In the Add a tab dialog box, choose Tasks by Planner and To Do.
4. In the Tasks by Planner and To Do dialog box, now select: ...
5. Choose whether to post to the channel about the tab and then select Save.