This is the name under which you wish to legally register your business. It is not necessarily the name under which you will be doing business, AKA fictitious name.
The legal name of a business typically contains a designator. The designator appears at the end of the business name and indicates the business entity type (e.g., corporation, incorporated, company, limited, limited liability company, or any abbreviation thereof, such as Inc or LLC). Be sure your designator matches the entity type you wish to register.
For a sole proprietorship, the legal name of your business is your first and last name.
Please note that the name you enter is subject to approval by the Commonwealth and may need to be changed if it is not available at the time you register.