Depending on elections made by the LLC and the number of members, the IRS will treat an LLC as either a corporation, partnership, or as part of the LLC’s owner’s tax return (a “disregarded entity”). Specifically, a domestic LLC with at least two members is classified as a partnership for federal income tax purposes unless it files Form 8832 and affirmatively elects to be treated as a corporation. For income tax purposes, an LLC with only one member is treated as an entity disregarded as separate from its owner, unless it files Form 8832 and elects to be treated as a corporation. However, for purposes of employment tax and certain excise taxes, an LLC with only one member is still considered a separate entity.
Washington "corporation", "incorporated", "company", or "limited", or the abbreviation "corp.", "inc.", "co.", or "ltd."; must not include "Bank", "banking", "banker", "trust", "cooperative", or any combination of the words "industrial" and "loan", or any combination of any two or more of the words "building", "savings", "loan", "home", "association", and "society" § 23B.04.010 Revised Code of Washington
Limited liability companies allow for a large variety of management structures based on your specific needs. Management structures for S-Corps are largely dictated by state and federal law. Management schemas for C-Corps are largely dictated by state and federal law. NPOs need to follow strict management laws to guard their non-profit status. Since Sole Proprietorships have only one member, there is no management structure.