UnityWebRequest how to upload a file/gameobject

I am on a team consisting of 2 novice programmers, I handle Unity and the other guy handles Json/Php/Database stuff.

We got a lot of stuff to work like [Post]registering, [Get]authentication/login, [Post]create new scenes, [Get]get list of scenes created but when it comes to saving the project. we want to upload any files/3d objects that were made/uploaded through AiImporter to our server. the Problem is only bytes or WWWform are the only thing that can be uploaded. I've done my research. it seems Serializing is the way to go. but you can't serialize a Game object though.. well its actually possible by buying some assets that can serialize object actually.. or so I thought. cause we were wondering if its possible to just import the object without serializing it. here's his photo of the database for upload.