Locking a board is a feature that prevents any current posts from being edited, new posts from being added, or other board edits/settings changes from being made. This setting is available to all board creators (and board admins and Org admins on Business, Pro, & Enterprise plans).
To lock or unlock your board:
1. When viewing the board select the Settings button with the gear icon (upper left-hand side).
2. In the dropdown, under Access & Privacy, you can toggle on Lock Board. Clicking the toggle will move it to the right to lock it and the left to unlock it. The label to the left of the toggle will also note if the board is locked or unlocked.
As the board creator/admin you are able to lock or unlock a board at any time.
Please note that a board is not automatically locked after it's delivered. Board creators/admins will need to manually lock their boards to prevent edits from being made.