Hi @A.Z, as Larry said there really are a lot of options around your account set-up depending on needs. This easiest way is just to start…and make adjustments/changes are you go along. I almost always recommend setting up as an organization. It just gives you the most flexibility and options to allocate work and task management. Setting up an organization in Asana | Product guide • Asana Product Guide
A few past forum threads which may also provide some help in your case are: Consulting with External Clients in Asana and Professional services firms: how have you set up Asana to balance internal vs external communications with clients? Hope this helps!