Can you make money after registering with the ministry of labour?

"Register with the ministry of labour" just allows you to write your own title and description for your sim's job. It doesn't give you any extra money and all you need to do is access this option from your phone. Your sim's job will then be "farmer/fisher/whatever else" instead of "unemployed", but you will have to earn money the same way you always have. I wasn't quite sure what you were asking, but I hope this helps.