Channeling is the act of relaying a message from a spirit to an audience, which could be just yourself.
Invoking has two different meanings depending on the tradition of magick you are using:
- Invoking calls the entity inside of your system so that you can feel what it feels to get information from it, or benefit from it’s energy.
- In some tradition invoking can mean summoning, more like evoking.
You can channel while invoking or without, they are not mutually exclusive actions.
I personally consider invocation to me a form of mild possession, but one where you are in control and conscious invited it. For others this does not qualify as possession: