You can share a new/existing whiteboard with all participants in a Teams meeting. That same whiteboard is available across all devices. 

You can also choose an existing whiteboard to share in a Teams meeting. This makes it easy to prepare a whiteboard ahead of time or continue working on a project outside of Teams.

To share a whiteboard in a Teams meeting:

1 - Select the Share icon in the meeting's share tray.

2 - Select Microsoft Whiteboard.

3 - The board picker view will open. Select an existing board from the list or start a new board.

If a whiteboard is already associated with the meeting, Teams will share that board by default. You can choose a different board to share by navigating to the Home icon in the top left.

Note: Surface Hub and Microsoft Teams Rooms devices primarily utilize resource accounts, and as such will default to sharing a new board or launching an already associated board.