Core comes standard with voice chat and all players can hear one another. But you can mute overly talkative and toxic players and it is very easy to do so. Muting someone only applies to voice chat.
First, you need to open the main menu. On the right is the social pane that shows all the active players. Simply find the player under the Players In Game category and click on their name. This opens a dropbox with the option to mute them. If the player is in your party, then their name will show up under the Party category. Muting someone is ideal for when you don't want to hear them.
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To unmute a player, the steps are much the same, only in reverse. Alternatively, if the player is harassing you and muting them isn't enough, you can also report and block them. These options are in the same dropbox that the mute player option is in. You can also go to their profile and report them by clicking on the three dots to the right of their name. Blocking someone will prevent them from being able to communicate with you through voice and text.