Where is the Find function in IntelliJ?
Select Edit | Find | Find in Files from the main menu. Shift+Ctrl+F Type your search string into the search field. Alternatively, highlight the string you wish to locate in the editor and press Ctrl+Shift+F. The highlighted string is entered into the search area by IntelliJ IDEA.
Search and replace a target within a project | IntelliJ IDEA Documentation.