Azure runbooks are a great asset for your automation account. They can be scheduled like jobs and are used to automate all kinds of operations that are related to your Azure infrastructure or even your on-premises workloads.
Not only can runbooks be executed from within the portal or using PowerShell. You can also create so-called webhooks for runbooks. These are essentially little API endpoints that are used to run your runbook with parameters from anywhere and by anyone with the correct URI.