To assign a retention policy for email in Outlook:

1. Create a folder in Outlook to hold all emails you need to retain for a certain period of time. To create the folder, Right Click on your Inbox or another folder and select ‘Create New Subfolder’.

2. Right click the new folder and select ‘Assign Policy’

3. Choose the appropriate retention policy. That policy will then be applied to all folders and emails stored within it. 

4. Additional folders and emails can then be moved into the folder and have the retention policy automatically applied.  

Please note:

Retention Wins Over Deletion: If you have both a retention policy to keep emails and another policy that automatically deletes them, the retention policy takes precedence. This ensures that nothing you expected to be retained is accidentally deleted.

Longest Retention Period Wins: Suppose one policy specifies a retention period of two years, while another policy sets it to five years. In this case, the content will be retained for the longer duration—five years.

Explicit Wins Over Implicit: Explicitly defined policies take precedence over implicit ones. If a user manually applies a retention label or tag, it will override any conflicting automatic deletion settings.