I tried this:
/tellraw @a {"text":"","color":"blue","extra":[{"selector":@p[score_wins_min=1},{"text":" has won the game!"}]}
but Minecraft doesn't know the command and doesn't do anything. Why? I want to make a Bedwars server.
I don't know what version you're playing on but this will work on 1.19.2 confirmed and most likely the recent previous versions as well.
I changed the command to work for you:
/tellraw @a [{"selector":"@p[scores={wins=1..}]","color":"yellow"},{"text":" has won the game!","color":"blue"}]
The command first selects a player that has a score wins
of 1 or more in yellow, and then the text in blue.
]
afterscore_wins_min=1
. It should be/tellraw @a {"text":"","color":"blue","extra":[{"selector":@p[score_wins_min=1]},{"text":" has won the game!"}]}
. I'm not sure about the JSON content though, here is another resource on that.