In other words, what is the vertical distance between the deepest and highest point on Earth where life is found?
Life has been discovered at the bottom of the Mariana Trench, 13 km below sea level. It's hard to get deeper than this, but I'm not sure if this really represents the bottom of the biosphere. Elsewhere at sea, microbes can be found many kilometers below the sea floor -- would we expect to find life far below the Mariana Trench?
In the other direction, the biosphere arguably reaches as high as 435 km, the maximum altitude of the International Space Station. If the ISS is disqualified, then that number would be much lower, but again I'm not sure exactly what it would be. The highest recorded bird flight clocks in at 11 km, though it's possible that microbes regularly get dragged up higher than this by wind.