Having other players take over the character for the session seem uncommon.
Getting into more detail on my groups:
In one out of two of the groups I
play in, we do this - if the missing player has shared the character sheet. If no char sheet for others to refer to, no takeovers. This is in part because we play in-person, and all but one of us play on paper sheets.
My other group I am a player, there are only 3 of us, and if 2 can play, we play, and ignore the missing player.
The third group I am a player in is a playtest of a non-D&D type game, so it doesn't really apply similarly, but if a player is absent, their character just poofs out, and returns the next time the player is there.
The two games I
GM, one is on 100% remote, and the players are mostly new. It's on Roll20, so I actually encourage them to take over other player's characters so they can learn what other classes do.
The other is a hybrid game. In other words, we play in person, but use Roll20 for our character sheets and maps - everyone brings their laptop. EXCEPT one player, who has a paper character sheet and looks at her sister's laptop at the map. It's because we started during the pandemic, and love being in person, but I love the virtual map resources I've paid for on Roll20 lol. Anyway, if a player is missing, then people can run their character in absentia.
Thus, of my 5 regular groups, 3 of them we allow others to play a character if the player is missing AND we have access to their char sheet.