If you are the one facing the issue of how to then you need to open Facebook app on your iPhone. Click on search icon which is located at the upper-right hand side of the screen. Tap to edit where it says recent searches to clear the search history on Facebook for iPhone. Lastly, at the top of activity log, click to clear searches option to smoothly clear off the search history on Facebook. These are the steps that you need to follow to clear Facebook search history on your laptop.