The Move Description command can only be used when labels are visible on the layout. Labels will not be visible when the Label Scale is set to a smaller value than the current drawing scale or when no items are enabled in the Label Enable section of the Display Options dialog.
Check the Display Options dialog (Options>Display) to determine if;
Refer to section 2.2.9 for detail regarding Description movement or section 2.10.3 for detail regarding Display attributes.