Azure resource locks protect resources from unwanted changes or deletions. You can set two states—Delete and Read-only. The Delete state means that the resource can be modified but not deleted, while the Read-only state means that the resource cannot be modified at all:
When you are setting the locks through PowerShell or the CLI, the Delete lock is called Do Not Delete.
For your Azure governance setting, Azure resource locks are quite important. Otherwise, contributors or higher-permitted roles may delete or edit the most important resources of a service by chance. This would mean that a good backup is required.