How to Use Fill Command in Minecraft?

How to Fill Areas in Minecraft with the Fill Command

Go to a corner of the area you want to fill.
Press F3.
Record your coordinates.
Move to the opposite corner of the area you want to fill.
Record the coordinates there.
Press the “T” key to open the Chat menu, and type /fill [your first coordinates] [your second coordinates].

How do you Replace a Block with Fills?

Type the command in the chat window and press the Enter key to run the command. This / fill command would replace all blocks in the fill region, including air. The replaced blocks will be dropped and can then be collected as if they were mined with a pickaxe or shovel.

What is the Command to Place Blocks in Minecraft?

Enable cheats in your world or Realm settings.
Turn on Creative Mode in your world or Realm settings.
Open the chat box and enter “/give [your username] command_block”
Place the block where you want it.