You can use Advanced Search when you need to search on a field that isn't available in the search bar, or when you need more detailed search options.
You can access Advanced Search by pressing the binoculars button in the toolbar 
or by going to Records > Advanced Search.
Advanced Search will open in the file you currently have open. For example, if you currently have an Object window open, Object Advanced Search will appear.
Advanced Search window with the Search Fields option selected
