When enabling Education Edition on Bedrock Edition, we have access to more blocks, building tools, and a few new commands. One of these commands is the Ability command. Granting a player flight with this ability will make the player seem to be able to fly normally, however all other players will see them teleporting between their flight position and the floor below them. when flying over water, the player will experience air bubbles, and when flying over lava, the player will catch fire.
I'm afraid we cannot help you with issue on Windows Phone. This platform is no longer supported, see https://www.minecraft.net/en-us/article/important-news-regarding-minecraft-mobile