Properties can be assigned with the Properties command in the Edit Menu.
Outside of any command, clicking on a visible physical property string allows the property to be edited. The property string must be close to or overlap the object. If the string is too far away from the object (if there are a large number of properties, or the object size is small) it can not be selected in this way. The user is first prompted for new text, then for a new property number. The clicked-on property will be replaced with the new values. If Ctrl-d is pressed at any time while responding to the prompts, the property will be deleted, with no replacement.
Properties with property numbers 7000-7104 are not displayed. These numbers are reserved for internal use and should not be assigned.
The Erase behind physical properties text check box in the Window Attributes panel, or equivalently the EraseBehindProps variable can be set to erase around the property strings, enhancing visibility.