Toggles write protection for fields and bookmarks in the document.
Protection is not intended to be an information security protection, it is a switch to prevent accidental changes.
Choose Tools - Protect Document - Protect Fields.
Choose Tools - Protect Document - Protect Bookmarks.
Toggles fields write protection. When checked, the fields cannot be edited or deleted.
Toggles bookmark write protection. When checked, the bookmarks cannot be deleted or renamed.