How does my world use command boxes to send messages?

Command box (currently only applicable to PC):

How to get it: the low version /give XXX 137 XXX is your player name, and you can fill in @ aallplayers @ p near player (from the command box) and the high version/givexxx mine craft: command _ block.

Command box Minecraft: command _ block137

Circular command box minecraft: repeating _ command _ block210

Chain command box minecraft: chain _ command _ block211

/Say (brackets don't, what did you say)

/give XXX (item id is not required for parentheses)

/tell XXX (brackets don't, what did you say)

The output information will be written into the chat box of all administrators in single-player mode or multi-player mode, unless it has been intercepted by /gamerulecommandblockoutfalse. Some commands may write text attached to their normal work in the chat box without being intercepted. (For example, the /say command will write a message in all players' chat boxes). Chat messages (such as commands /me, /say and /tell) prefixed with the player's name usually use @ as the player's name. If you have named the command box with anvil before placing it, use that name.