on an eForm and in the schedule, and also by green text in the Data Browser. See example
Subject data can be frozen or locked to prevent anyone making changes to it. You can freeze/lock questions, eForms, visits or entire subjects.
A full audit trail of freeze/lock operations can be viewed in the Freeze/Lock History Browser.
You may only freeze or lock subject data if you have the relevant permissions to do so. There are separate permissions governing freezing, locking, unfreezing and unlocking. For example, it is possible for your system administrator to set up a user role which allows freezing and locking but not unfreezing or unlocking.
You can freeze or lock data on a server and at a remote study site.
You cannot freeze or lock data in a study that has been assigned the status 'Suspended'.
You cannot make any changes to frozen data or add comments, although you can still create SDVs, DCRs and Notes.
Frozen data is indicated by the freeze icon on an eForm and in the schedule, and also by green text in the Data Browser. See example
You cannot make any changes to locked data, or add comments, raise DCRs or create SDVs. You can create notes for locked data.
Locked data is indicated by the lock icon 
on an eForm and in the schedule, and also by red text in the Data Browser. See example
You can lock frozen data, but you cannot freeze locked data.
The status of a question on an eForm may be set to 'Not Available.' This is not the same as the question being locked. Data can still be entered if a question is marked as 'Not Available'.
