How can you design a map yourself in Minecraft?

Minecraft has maps that show the surroundings. But I want to design this card myself.

I build Ikea in Minecraft and I want to make the Ikea guide on the Kate.

How do I do that and does it also work in multiplayer?

I don't know exactly, but go to the card table and see if you can do something.

Take the shovel in your hand and get started.

You can build that in bulk in the exact area shown on the map