How to upload a transparent texture and have it display on a plane with transparency?

Hi InaCentaur!

If your objective is to have a transparent plane that has any sort of visuals on it or is more than an invisible object serving as a collider, you do need to assign a material to the mesh outside of the Desktop Editor for it to work. Even if you have a texture asset that uses the alpha channel for transparency, applying it to a mesh that does not have a transparency-supporting material assigned to it will not produce transparency. The material names and texture file suffixes assigned to the meshes help inform the Worlds on how to unpack and display the texture information. You can find the materials guide here, and the materials to look for are the _Transparent, _Blend, and _Masked materials.
Happy creating!