A search box or search field is a common GUI element of computer programs, especially in file and web browsers and in web sites.
It is basically a type of text box, the contents of which are to be searched for in a database. It is commonly coupled with a search button (sometimes indicated only by a magnifying glass symbol) or a submit button.
Some sites do not enable the search box unless you are logged in. The search box on this site is enabled for any user – logged in or not.