About Google Calendar Push Notification

Solution 1:

Can we register local host as a receiving url.

No, you can't. The Google API sends HTTPS POST messages, and for the HTTPS to work it needs a SSL certificate pointing to your domain.

How to Register the domain.

There are no specific requisites about domain registration. You should register it following the usual procedures. Please remember to perform a domain verification on the Cloud Console after the registration.

What does chanel means in this context?

A channel configures the path for your push notifications. It contains the URL where you will receive the messages and notification settings. A channel is set to listen to one resource (i.e. a Calendar resource). When the resource gets updated, the Google API will send a HTTPS POST message to your channel URL.

Can you share a sample which can show working push notification of calendar?

There are many different examples on the linked docs. If you need help on a particular topic, please be more specific about the related step.