"LLC" and its variations (LLP, PLLP) is a State organizing designation. If you have one member, that's Individual. If you have more than one, that's either a Partnership (Form 1065) or they may have elected to be treated as an S Corp (Form 1120-s), so, you have to ask the client. Sole Proprietorship means Individual. Both single-member LLC/LLP and Sole Proprietorship are the same for functional and tax purposes = they are the Schedule C of Form 1040 filing entity and both require an EIN if there are employees and the single owner cannot be their own employee or on payroll. It seems you have what you need.