You can download "Minecraft" maps that others have made and play on them yourself. "Minecraft" maps can be downloaded for free from community sites like Minecraft ...

Available on Minecraft: Bedrock Edition and versions that run off of its code (Education and Pocket Editions), Minecraft Marketplace is the primary means of downloading and accessing custom content ...

Though Minecraft's world map is massive, it does not take up a lot of space on a device. The game's worlds are essentially only the information of the seed and what has been tweaked by the player.