You can add other users and contacts from your phone book to favourites to have them in one place and have them show up first while performing an action, e.g. transferring a call.
Users can be added/removed from favourites by clicking "Add to favorites" or "Remove from favorites" on user’s details screen as shown in above.
Contacts from phone book can be added or removed from your favourites by clicking on it and choosing Add to favourites or Remove from favourites, as shown below.
"Add to favorites" adds contact to favourites