Phantom Power for practical purposes is powering a microphone with its signal cable. Some mic types require power to operate and some don't.

A practical check is to know that you always need to have three outgoing connections to send phantom power out of a recording device (in this case your camera).

XLR has three pins in one plug.
TRS has three separate metal connections on one plug (TRS stands for the three which are tip,ring,sleeve).

Because of this using a simple cable adapter that converts from three pins on the mic end to two connections on the camera side won't work. Obviously one of the three pins isn't connected in the adapter.

A quick check of your owners manual for camera or recording device will tell you if it's capable of outputting phantom power. Look for the ability to switch the phantom power on and off.. most devices that will supply phantom power allow you to turn phantom power off to save battery power.

The important part of your answer is the solution. How do you use a mic that requires phantom power with your camera that does not provide phantom power.
Two ways. First some mics that require phantom power can power themselves with an on-mic battery. Second you can buy an adapter to go between the mic and the camera that provides phantom power. There are many powered adapters available that will do this.

So simple adapter cable no. Phantom power adapter device yes.

So why use phantom power at all? Well the mics that use it are much more sensitive and can pick up fine details in the sound they are recording.
An added bonus is with three wires in the mic cable the signal can be transferred in a way that cancels noise that is picked up by the cable (you aren't an engineer so I won't explain how it works).
If you only use a mic cable that is a few inches long the noise picked up isn't an issue so you can get away with a two wire cable.
Anything longer do yourself a favor. Use the much more capable three wire cable with a phantom powered mic. You get more detailed sound and low noise at the same time.