When playing Minecraft Bedrock Edition offline, I can't create (or edit) skins in the changing room.

I only have Android and Windows 10, so I can't check it on other devices, but when I try to play Minecraft offline, I can't create (or edit) skins in the changing room.

However, when you go online, you can create (or edit) skins.

 

The image is the screen of the game taken in Japanese.