So…yeah. Unfortunately, this doesn’t work on servers. But it will work in any singleplayer/multiplayer worlds! 
The way this pack works is there are thirteen packs. Each covers two letters, such as X and Z. The mobs starting with those letters, such as zombies, will fall in that pack. For mobs with multiple variants, such as horses, it won’t start with C-D for the creamy horse, all of them will be under G-H.

As you probably noticed, I am an allay in the picture above and have zero armor, but my armor points are filled. The armor will not show up only for you, however, you will be able to see what other players/mobs are wearing.

(Note: this is not the default look of the enderman).

In each pack, there will be a mobs.txt, which will display all of the mobs found in it. In some cases, there may be a removedmobs.txt, which are mobs with issues that I cannot put in this pack. Luckily, barely any mobs had to be removed. You might also find a misshapenmobs.txt, which is a text file letting you know that some mobs had issues with their geometry file and have issues with the way they look.

In some cases, you may not be able to see the item you are holding other than in your hotbar. Other players cannot see you as a morph unless the pack is activated in the world, whereas everyone will be the mob that you select in the subpacks.

Please note that this will not work without the default Minecraft resource pack anywhere in your files. You can find that here: https://github.com/Mojang/bedrock-samples/tree/main. Click on ‘code’ and ‘download zip’. Uncompress it and install the texturepack, and you are good to go.

The reason this is is because, in most of the morhps, I do not provide the texture file for it in the pack. The filepath will lead to anything that has the path, including other resource packs if you have them active in your global resources.

That's really all you need to know about this pack. Happy Halloween everyone!