Since all 3 countries (Spain, France and Portugal) are Schengen countries, you won’t face a hard border crossing. In other words, there are no border crossing points and you don’t have to show documents when crossing the border.

There is no border crossing to speak of - these are Schengen and EU countries making border crossing similar to crossing between states in the US. Just drive on through. Obviously have your passport handy just in case but under normal circumstances you won't be stopped at all, there will be no border guards or checks.