I've got a business idea and need some help with planning and costing etc, but a guy from Austrade says I need an ABN for him to be able to help me move forward. He's been really helpful so far in a general sense, so I'd like to be able to work with him. I've started to fill out the online ABN application but I'm stuck re 2 things: 1) the entity- sole trader or company. Can anyone give me brief overview of options re this? It would be just me initially but I may pull in hubby and others to help later on. 2) the nature of the business. There's a drop down menu where you need to select what the business will do. I'm still at the planning stage though and have a couple of different options. Is it easy to change the nature of the business after getting the ABN from selling one product to another, for example?