How to Change Game Mode in Minecraft

Guide Java Bedrock

Quick answer: Run /gamemode creative (or survival, adventure, spectator) with cheats on. Java shortcut: hold F3 and tap F4 to open the game-mode switcher. Bedrock: the world settings also have a default game mode dropdown.

What you need

Cheats enabled (Java: Open to LAN trick works)
Java: keyboard for the F3 + F4 switcher
Bedrock: world settings access

Step by step

With cheats: open chat (T) and run /gamemode creative, /gamemode survival, /gamemode adventure or /gamemode spectator.
Target other players on a server: /gamemode survival PlayerName - operators only.
Java shortcut: hold F3 and tap F4. The game-mode switcher opens; tap F4 to cycle modes and release F3 to apply. Spectator is included.
Bedrock: open the world settings and use the default game mode dropdown, or run the same /gamemode command with cheats on.
Creative gives infinite blocks and flight; adventure restricts block breaking for maps; spectator lets you fly through blocks and watch mobs.
The mode sticks per world until you change it again - no need to re-run the command.

Java vs Bedrock

Bedrock locks the world game mode behind the settings dropdown and disables achievements if you switch a survival world to creative. Java has no achievement lockout.

Versions: The F3 + F4 switcher exists in all current Java versions (1.16+). The /gamemode command works on both editions.

Frequently asked questions

Does switching to creative disable achievements?

Bedrock: yes, permanently for that world. Java: no - advancements keep working.

What is spectator mode?

A no-interaction mode: you fly through blocks and can click mobs to see through their eyes. Java and Bedrock both have it.