Soul Shatter — ruling 1

As Soul Shatter resolves, first the opponent whose turn it is (or the next opponent in turn order, if it's your turn) chooses a creature or planeswalker they control with the highest mana value among that player's creatures and planeswalkers, then each other opponent in turn order does the same, knowing the choices made before them. Then all of the chosen permanents are sacrificed at the same time.

Soul Shatter : règles, fonctionnement et interactions (MTG)

Soul Shatter is one of those cards players keep asking about. Here is, in plain words, what its official text says, the rulings published by Wizards of the Coast, and the combos players actually run.

Official card text

Each opponent sacrifices a creature or planeswalker with the greatest mana value among creatures and planeswalkers they control.

How it works : Soul Shatter

Original English text — Wizards of the Coast / Scryfall

#1September 25, 2020· Wizards of the Coast
As Soul Shatter resolves, first the opponent whose turn it is (or the next opponent in turn order, if it's your turn) chooses a creature or planeswalker they control with the highest mana value among that player's creatures and planeswalkers, then each other opponent in turn order does the same, knowing the choices made before them. Then all of the chosen permanents are sacrificed at the same time.
No other card is named in this ruling.