What does Refund pending mean?

Got a refund just there on my son’s >18 account but the money isn’t actually in the account it just says pending, is this normal? How long will it take for the money to be in the account?

Got a refund just there on my son’s >18 account but the money isn’t actually in the account it just says pending, is this normal? How long will it take for the money to be in the account?