If you are a sole proprietor, you could use your own family name (but are not obliged to do so). Furthermore, a trade name must not be confusing or misleading. And most important your trade name must still be available and can’t cause confusion with the names of other companies. So you’ll have to check the legal names in the Crossroads Bank for Enterprises (BE) or in the Chamber of Commerce (NL). Also check the trade names of other companies that offer the same products/services in the area you want to operate in. As there is no obligation to register trade names, you’ll have to check these trade names online, check domain names, and so on. And last but not least, check the trademarks registers for the products/services you want to use the name for, since a trademark owner can stop you using the same name (see the smart guide on trademarks).