A business name is a sole proprietorship. It is not a separate legal entity. Its assets and liabilities are personally yours. Its tax is done under personal income tax.
That can be enough for a small, one-operator, B2C trade. It is cheap to start on CIPA — name reservation about P20, full registration path around P170. You appoint a proprietor (you, or a company trading as the name). You do not appoint a secretary for CIPA — but banks still ask for KYC from a “secretary” on letterhead.
What it cannot do easily
You can hold a residential trading licence. You cannot comfortably tender at scale or take large contracts with government and big institutions. Growth hits a wall that structure, not effort, put there.
“Can I convert later?”
People ask this every week. You do not really convert. You cease the business name (about P150) and register the same name as a company. Time, cost, and mess — avoidable if you chose the structure your future needed at the start.
If you mean to grow, build on a Pty Ltd. Separate legal person. Shareholders, contracts, capital, and one day a listing path. That is the work we do on Basic Company.