Webhooks are user defined HTTP callbacks, which are triggered by specific events. Whenever that trigger event occurs in the source site, the webhook sees the event, collects the data, and sends it to the URL specified by you in the form of an HTTP request.
To create a Webhook subscription, go to;
1. Settings > Webhooks
2. Click Create Webhook Subscription
3. Fill in the webhook details according to your trigger and click Save Subscription.