The Annotations API lets you manage your annotations programmatically. Annotations are text descriptions tied to a time that will show up in reports such as Insights to let users know something meaningful occurred at that time. You can use this API to get a list of your project's annotations, edit them, create them or delete them.
Roles & Permissions
To modify annotations (create, delete, or edit), you or the Service Account being used must have the role of at least Analyst.