The fulltext search allows the user to search in the entity, which he selected in the Connect to dropdown list – archived mailbox, File archive root or SharePoint archive root site.
If you move your cursor over the Type search text here… field, a pop-up with some search filtering options and recent search will appear.
If the user has access to more than just one mailbox, he gets the option to Search everywhere – it will allow him to search in all of the mailboxes he has access to. If the user has access to only one mailbox, Search everywhere is not enabled.
If the user does a search using Search everywhere and there are models which support Fulltext search and also those which don’t, a search mode selector will be visible. If the user selects Full-Text, it will search only in models which support Fulltext search. If the user selects Classic, it will search in models which support only the classic legacy search.
In this case, the user has access to entities firstname.lastname@example.org and email@example.com
so if the user searches for a phrase or applies a filter (requirement) that more items of the mailboxes meet, it will look like this: