verb
BAD : You can bring as many friends to the party as you like. Everyone is welcomed.
GOOD : You can bring as many friends to the party as you like. Everyone is welcome.
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welcome (verb) = greet a guest or visitor in a friendly way when they arrive: 'Her Royal Highness was welcomed at the airport by a party of Cabinet Ministers.'
If you are pleased when someone comes to stay at your house or comes to your party, they are welcome (adjective), (WITHOUT d) : 'You're always welcome to stay here, you know.' 'Aunt Edna always makes us feel welcome.'