Watchers are project members, roles, and companies, that are able to see an issue, leave comments on it, and receive email notifications when the issue is updated. They can also see the other watchers on the issue. Watchers can't edit fields, change assignees, or add other watchers unless they have been given those permissions separately. See Issue Permission Levels for details about how issue permissions determine actions available to certain project members.
Adding watchers is helpful for teammates who need to stay up to date, but are not contributing to the issue's resolution.
You can add a watcher when you are:
To add a watcher:
Click the Watchers drop-down list.
Select the checkbox for a member, role, or company that you want to add as a watcher.
Who you can add as a watcher varies depending on your permission level.
See Issue Permission Level for more permission-specific information.
When you assign an issue to a project member, they are automatically added as a watcher. If you remove or change the assignee, that project member will not be automatically removed as a watcher. You can remove them manually by editing the Watchers field.
The member will no longer be able to view the issue, unless they have access through their permission level.
Who you can remove as a watcher varies depending on your permission level.
Watchers will receive a notification for the following actions:
The frequency of issue notifications is set in your project's notification settings.