If you did not enable Find My before your phone was stolen, it cannot be turned on remotely, nor tracked. Apple provides simple things which require no effort to help in situations like this, but they need to be turned on before something bad happens.
You will never find this phone again. Apple does not get involved in lost or stolen devices, so there is nothing Apple can or will do for you. All you can do is report the phone stolen to your cellular provider and ask them blacklist the phone.
You should also, if you haven't already done so, change your Apple ID password. Here is a link on how you can do that --> Change your Apple ID password - Apple Support
If you had credit cards on your phone, I would cancel all your cards and have them reissued so whoever is in possession of your phone doesn't go on a shopping spree in your name.