Group is a social function in Overwatch. It allows players to play together, to have their own space to communicate. At the end of every Quick Play, Play vs. AI, Competitive Play, Weekly Brawl and Practice vs. AI, every member in a group will receive 20% experience bonus (no matter how many members are in the group). The group's default color is green, as seen in group's voice chat channel, or team member's name in game.
A group has a leader, who is the first one to form a group. A player can be group leader if the former group leader forfeits their title to them. If the leader leaves the group, the player who has stayed the longest time in the group will be the next leader.
The group leader is responsible for finding a match. A group will always join a game together and leave the game together, following its leader.
Forming a group
A group leader can invite members by right click on players' names from a number of places, including Social menu, chat box, hero assembly in the pregame, etc. If the invitation is accepted, that player will be added into the group. Player can block invitations in Options menu. Group members can also invite other players if a leader has that option on. Players can request to join group with their friend through the Social menu; group leaders can also deny or block any request. Players Automatically Join Or Create a group if the "stay as team" option is selected for at least 2 players.
The group leader can limit the members of their group to everyone, or their friends, or for only the ones who received the invitations.
Managing a group
All group members will be shown in the upper left corner in the UI (except when a game is playing). This is where a leader can remove a player from a group or leave the title to other members, by right-clicking on members' icon. A member can also quit the group by right-clicking on their name.
The Group menu on the Social menu can be used to do the same things. In addition to those functions, the Group menu can be used to switching voice chat channel from Group to Team, or mute a specific player in the group.
A player can also quit a group by quitting a game when they are not a leader. In the leader's case when they quit a match, they have options to quit the game alone, or with the group. Quitting midgame as a group will count toward the Leaver Penalty for each of its members.