The Game Is About Learning
Avoiding spoilers, the game is all about learning. Many of the game’s mechanics will take time to understand, but that is also the intent. Part of the fun of Phasmophobia is running around with your friends not knowing anything about the ghost you are hunting.
However, one of the more important mechanics you should be aware of is that your in-game mic matters. The ghosts can hear you, and EVP sessions exist when using the spirit box. This is a game fully focused on immersion, and so it is best to try to allow yourself to be pulled in.
For those who may not be up to date on their ghost hunting acronyms, EVP stands for electronic voice phenomenon. This means when you hear an unexplained sound or voice on a recording. A spirit box is used in conjunction, quickly switching radio frequencies akin to Bumblebee in the first Transformers movie.
In real life, this results in you asking a question such as “Are you there?” and and a crackling radio voice saying “Yes.” In game, the results can very widely based on the input from your mic.