How to create a custom notification channel?

Dear HA users,

I’m new to HA, and I’d like to know if it’s possible to create a personal notification channel, via a POST request, so that it’s available in all sensor, scene and other automations? I’d like to be able to reuse this call in a simple way in order to be able to call a local TTS service to inform people in my home.

Thank you for your answers,
Best regards,
Jean