Being able to lock and unlock records is very helpful for ensuring data integrity. In Salesforce Classic, there used to be a lock icon to let you know when a record was locked.
This hasn’t made it over to Lightning as of yet. As a result, you can use the Locked Record Notifier to let Users know that the record is locked and in addition, you can use your own note.
Simply go to Lightning App Builder, select the Locked Record Notifier, drag it to where you would like it to show, and enter some text. If the record is unlocked during the Lightning App Builder Page edit, you’ll see it blank, like below, as the Locked Record Notifier will not show unless a record is locked.
If the record is locked during the Lightning App Builder Page edit, you’ll be able to see the preview.
The component will automatically show if the record is locked and will not show if the record is unlocked. This is a great way to let your users know a record is locked, and give them additional information if needed!