Just open the
.mcworld file with an archiver e.g. WinRAR. Then go to the
behavior_packs folder and extract your behavior pack. If the behavior pack requires a resource pack, then you will need to extract that too. You can find it in the
To install your behavior pack and/or resource pack, you will need to go to the Minecraft Bedrock directory. Normally, you can find it here
C:\Users\(username)\AppData\Local\Packages\Microsoft.MinecraftUWP_(a bunch of letters)\LocalState\games\com.mojang\
Inside that directory, there will be two folders, one called
behavior_packs and the other called
resource_packs. Put your behavior pack(s) and resource pack(s) in their corresponding folders. Then open/restart Minecraft and now you can use the packs in other worlds.