If a commander is in a graveyard or in exile and that object was put into that zone since the last time state-based actions were checked, its owner may put it into the command zone. This is a state-based action. See rule 704.
July 3, 2020 · Core Set 2021
If a commander is in a graveyard or in exile and that card was put into that zone since the last time state-based actions were checked, its owner may put it into the command zone. This is a state-based action. See rule 704.
April 17, 2020 · Ikoria
If a commander is a melded permanent or a merged permanent and its owner chooses to put it into the command zone this way, that permanent and each component representing it that isn’t a commander are put into the appropriate zone, and the card that represents it and is a commander is put into the command zone.
May 3, 2019 · War of the Spark
If a commander is a melded permanent and its owner chooses to put it into the command zone this way, that permanent and the card representing it that isn’t a commander are put into the appropriate zone, and the card that represents it and is a commander is put into the command zone.
January 25, 2019 · Ravnica Allegiance
If a commander is a melded permanent and its owner chooses to put it into the command zone this way, that permanent and the card representing it that isn't a commander are put into the appropriate zone, and the card that represents it and is a commander is put into the command zone.
July 22, 2016 · Eldritch Moon
If a commander is a melded permanent and its owner chooses to put it into the command zone this way, that permanent and the card representing it that isn’t a commander are put into the appropriate zone, and the card that represents it and is a commander is put into the command zone.