致意 is a formal separable verb (离合词) meaning to convey greetings or to pay one's respects. It's commonly used in written or polite contexts, such as when sending regards to someone through a third party or in public speeches. The verbal part 致 can be separated from 意 by a measure word or aspect marker, e.g., 致了一个意 (paid a greeting). The object of the greeting is introduced by 向 (to) or 给 (to).