Chalkboards are special blocks in Minecraft: Education Edition that allow players to write and display text in their worlds. Chalkboard actually refers to a collection of three different blocks: Slate, Poster, and Board. These boards are distinguished primarily by their size: 1×1 (slate), 2×1 (poster), and 2×3 (board), which dictates their text capacity. Boards can be found in the Items tab in your Inventory.
To place a board, select it in your inventory and right click to place it in the world. Boards can be attached to walls as well as the ground. To edit the text, right click on the board and enter text into the space.
For more information visit our Minecraft: Education Edition knowledge base.