You can teleport to Mushroom Island with the tp command, or you can use a seed and get lucky enough to be born there.

/tp @s x y z(xyz are the coordinates of Mushroom Island)

Mushroom Island is literally heaven on earth, countless food, no monsters, but also no resources for mainline survival, in short, it's a paradise.

Mushroom Island Seed: 3215399.

Game Content

Introduction

Players are free to choose the game modes (Survival, Creation, Adventure, Extreme (Java only), and Sidekick (Java only). Experience different and interesting gameplay in various modes, enjoy fighting monsters and adventures in Survival Mode, and enjoy being a creator in Creation Mode.

The game is based on the theme of players freely creating and destroying different kinds of cubes in three-dimensional space. Players can complete the game's achievements (progress) by destroying or creating elaborate buildings and art in single or multiplayer mode, or by collecting items to explore the map. Players can also experiment with gameplay such as redstone circuits and commands.