We usually can't see how the content is protected when you only give us a screenshot but it is likely that the content is a 'content control' which has a number of settings that might protect it and its content.
This
page created by Greg Maxey has a good introduction to Content Controls and it includes information about user restrictions which might be the issue with your doc.
If this isn't the issue, you will need to attach a sample document so we can find out what type of protection is applied to it.