THIS IS NOT BEHAVIOUR PACK OR COMMAND BLOCK CREATION.

This is a world that uses the hidden spectator mode. There are no behaviour packs or commands in this world it is just a world with the hidden spectator game mode enabled. 

What is spectator mode?

Java

In Minecraft Java you can simply type “/gamemode spectator”. Once in spectator mode you cant break blocks but you can fly through them. You also get special buttons in your hot bar that do certain things. You can left click mobs to see their point of view.

Windows 10, Bedrock, Console And Pocket Edition.

There is no command to get spectator mode, you have to change world files to get it. (Ive provided downloads to 3 different worlds that have spectator mode enabled) You can break blocks, and after you break them you can pick them up like survival, you can place the blocks but they won’t go from your inventor. You can’t see mobs point of view they will just take normal damage. You can pas through blocks and hover in the air. Your inventory is like the creative inventory but you can’t take blocks.

To get spectator mode you need to change world files, so I have provided downloads to pre-changed worlds.
There are 3 different worlds options:

creator: TRANT