All my F keys are predefined. (I'm on an iMac and use the default Apple functions frequently.) I've found multiple places that say F3 brings up Search in Blender. It seems like almost everything in Blender can be reached in multiple ways, such as a keyboard shortcut, a menu, or through a pie menu or any of the bars at the side or top of an editor window.
How, other than F3, can I get to Blender's search function? Or is there a way to add an icon somewhere I can click on to access it?