I want to bake muffins for pocket money and sell to an industrial area but not sure what legalities i need.?

I am a full time mother and its so hard to find work out there for school hours and no school holidays, so I know I am good at baking and thought maybe some slices and muffins would be great to offer businesses in the industrial area, just door knocking, I remember years ago a lady used to come into where I worked doing just that and proved to be very popular.