Not necessarily. A company's 'legal' name is the name of the company in the records of the state in which the company is legally formed.
The name under which a company does business (i.e., the name you'll put on the outside of your skyscraper in a few short years!) is usually referred to as a 'trade name'. Trade names and legal names are often identical, but not always.
To keep things simple, we recommend that your trade name and legal name be the same - but they don't have to be. In this Starter Guide, you're selecting your trade name.