Hi @J-3804,
Welcome to post Q&A forum!
This feature is not enabled by default. To enable it, you need to create a retention policy that includes a notification action. This action sends an email to the user or a group of users before the retention period expires, notifying them that their content is about to be deleted.
Regarding your second question, you do not need to assign E5/F5 compliance and retention to every user. You can assign these licenses to only those users who need to receive notifications for review. For example, if you have a legal team that needs to review content before it is deleted, you can assign E5/F5 licenses to those users.
https://video2.skills-academy.com/en-us/microsoftteams/retention-policies
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