You can't turn location on remotely unless you've already got an app installed that can do that. Some security apps used to be able to do that, not sure whether they can with current Android versions.
Google's "Find My Device" (formerly Android Device Manager"), the thing most likely to be set up (because it's pre-installed on most devices) cannot do this. But it can make the phone ring for 5 minutes if it has been enabled on the device at all, so if it's possibly lost around the home or workplace that might be worth a go.