We invite that when sending your 3D files:
To create a zip for each 3D scene (We take all types of file formats : .max, .mb, .obj, .fbx, .dwg ... ) and at least one 3D view , a cross-wired, and a few useful information about your files, numbers: Verts, Edges, Faces, tris, UVs , Textures.
If possible, and to increase your chances of selling, you can send multiple export formats for the same file like OBJ FBX DWG ....
And finally, your credits.