According to police, Papalia used peoples money to fund his own business ventures that would, in turn, give the false impression there were legitimate returns on invested money.
All up Papalia scammed $18,935,958.89 off 47 clients with transactions ranging between $5000 to $3.95 million.
Papalia was assessed by a mental health nurse before making a brief appearance in court on Friday.
He made no application for bail and was remanded in custody, due to appear in court via video link next month.
Detective Senior Sergeant Ken Foster said the investigation was ongoing and "very complex", involving a large amount of historical financial transactions.
Papalia faces 47 charges of stealing by direction with each charge relating to an individual.
Get the latest breaking news from SCA newsrooms around Australia. Short, simple and everything you need to know.