Understanding planet formation under different environments constrains theory of planet formation and provides a pathway for future missions in search for habitable terrestrial planets. Planet formation and evolution is a complicated physical process with many variables. Each variable affects the outcome of planet formation, e.g., planet occurrence rate. My research focuses on quantifying the influence of these variables on planet occurrence rate with a suite of observational studies. In particular, I will show that metal abundance affects not only gas giant planet formation but also terrestrial planets. Terrestrial planets occur more frequently around stars with higher metallicity. In addition, I will provide observational evidence that planet formation in binary stars is different from that in single stars. A stellar companion in a binary star can significantly influence the formation of planets. The influence varies as a function of companion separation, companion mass, and planet radius.