Planner sends email and push notifications for a variety of reasons. Some notifications can be controlled by plan members, and others by group owners.
In Microsoft Planner, notifications are designed to keep you informed about activity in your plan. You can receive notifications for a variety of events, such as when a new task is assigned to you, when a task is completed, or when a task's due date is approaching.
By default, Planner sends you email notifications for certain events, such as when you are assigned a new task. You can also choose to receive push notifications on your mobile device, or you can choose to receive notifications in the Microsoft Teams app if you use it.
To customize your notification settings in Planner, click on your profile picture in the top right corner of the Planner web app, and then click "Notifications." From there, you can choose which types of notifications you would like to receive and how you would like to receive them. You can also choose to turn off all notifications if you prefer.
It's important to note that notification settings are specific to each individual user, so you will need to customize your own notification settings separately from other users in your organization.