A chest appears after the boss falls. Everyone can see it, but that does not tell you whether everyone receives the same reward, whether one shared item is being allocated or whether each player has a separate result.
Games use different loot systems, and a title may change them between modes or updates. Check the current in-game explanation and official documentation for the activity you are about to play.
Ask three separate questions
Who receives a roll or reward? Personal loot generally assigns outcomes individually, while a shared drop needs some method of allocation. The exact implementation matters more than the label.
Who can claim the item? Visibility on the ground or in a chest is not always permission to take it. A party setting, timer or role restriction may apply.
Can it be traded afterwards? Binding, eligibility and trade windows can limit what a player may pass to someone else. Do not promise a transfer before checking the item’s actual rules.
Agree before the attempt
For a regular group, state the allocation method in advance and confirm it when new members join. An agreement made after a rare item appears is much harder to discuss fairly.
For an invented example, a group might use the game’s built-in roll system for a shared drop. That is different from each player receiving a personal item and choosing whether a permitted trade is possible. The same celebratory screen can conceal very different decisions.
If a result seems wrong, preserve relevant screenshots and use the game’s support route where appropriate. Avoid accusing another player based only on what your own interface displayed.
Clear loot expectations do not guarantee a desired item. They make the social part of the encounter less likely to become the hardest mechanic after the fight.