What is the name of the movie where at the end of it some guys were going to commit suicide and those who were at the party had to decide by their cellphones if they lived or died?

The movie you're referring to is called "Nerve," released in 2016. In the film, participants engage in a high-stakes game of truth or dare, where they must complete increasingly dangerous challenges. The climax involves a situation where the lives of characters are put at risk, requiring others to make life-or-death decisions through their phones.