Just bind it to whatever function you need and when if the F key is bound to something that would collide with your new binding, a prompt will show up and lets you overwrite it.
The only think I know of that could be bound to F by default would be "thrust down" in the ship, which shouldn't be a problem.
The controls in the on foot section of the bindings are all I think unique which means you can bind what you want to them, as @Chris Simon says if F is bound elsewhere you will get a pop up telling you where it is bound and giving you the option to overwrite or cancel.
I have F bound to “move vertically down“ in the Galaxy Map and enter FSS mode while in the ship I don’t think it is bound to anything else.