Microsoft's Electronic Discovery Reference Model
A schematic posted here on docs.microsoft.com does an excellent job of showing how Microsoft 365 can be used at each stage of the EDRM.
Legal hold notifications are distributed to custodians, and their activity is audited.
Data from multiple locations can be transferred to a central repository for review.
The Advanced eDiscovery tools which come with Microsoft 365 facilitate the preservation of data with the goal of retaining it for processing and review in legal matters.