Summary: https://docs.microsoft.com/en-us/exchange/security-and-compliance/in-place-and-litigation-holds
Place all mailboxes on hold: https://docs.microsoft.com/en-us/Exchange/policy-and-compliance/holds/place-all-mailboxes-on-hold?redirectedfrom=MSDN&view=exchserver-2019
Place a mailbox on litigation hold: https://docs.microsoft.com/en-us/Exchange/policy-and-compliance/holds/litigation-holds?redirectedfrom=MSDN&view=exchserver-2019
To place an Exchange Online mailbox on Litigation Hold, it must be assigned an Exchange Online Plan 2 license.
Jason works as a project specialist at an IT MSP in Erie, Pennsylvania, USA. He’s an IT/security professional with 19 years experience.