To search the database, you have to provide at least one search criteria (firstname, surname, city, email or country). The text entered could be partial of a text, for example; entering "Lon" (without quotes) in City would return all addresses with London and London, Ontario as City name. Similar, entering "Ab" (without quotes) in Firstname, would return all names containing Ab such as Abbas, Abdul, Gulamabbas etc. 

If you enter text in more than one field, the search will be done using AND operator. For example, entering "Abbas" in Firstname and "London" in City would return all address with Abbas in Firstname registered under the City London.