
Explanation:
To declare documents and emails as records, you use retention labels that mark the content as a record or a regulatory record.
You can then either publish those labels in a retention label policy so that users and administrators can apply them to content, or for labels that mark items as records (but not regulatory records), auto-apply those labels to content that you want to declare a record.
https://learn.microsoft.com/en-us/microsoft-365/compliance/declare-records?view=o365- worldwide