You should use the project file on Monstermash.zone since it will work there, but the regular pill bottle mesh can be used in anything that uses OBJ, MTL, and GLB files.
The project file is meant to be imported into Monstermash.zone but keep it inside of the zip file when you do it or else it will not work. none of the other files need to be imported into Monstermash.zone and will not be able to be, but can be imported into other 3D software.
This goes well with My Pill Model.