Tesla Model 3 with hitch can take a bike rack or storage box
Tesla likely didn't envision the Model 3 for towing and it's not rated to do so even if you install an aftermarket tow hitch. However, a bike rack is acceptable.
Recently, JerryRigEverything showed the installation of a tow hitch on a Tesla Model 3 (owned by Ben Sullins from Teslanomics). The purpose of the project was a bike rack, but just for the demo, the car was pulling almost a 2,000lb (907kg) trailer out on the road.
See Also
The Hidden Eco Hitch comes from Torkliftcentral at almost $400 and is removable, so you can disconnect the hitch when not in use. There is no connection for brake lights and installation does require cutting a hole.