Logos are visual representations of a business. The logos of most major businesses include a recognizable image or font. Some famous logos, such as the golden arches or an apple, are just as recognizable as the name of the business they represent. Logos can be simple images that do not have to contain the business's name, so an LLC does not have to put the abbreviation "LLC" in its logo.
A limited liability company, or LLC, provides liability protection to the business's owners, called members. To provide such protection, the LLC must meet state standards, which generally require the LLC to meet certain name requirements before it can register with the state. Typically, states require limited liability companies to use an identifying phrase or abbreviation like "LLC" in their names, such as "ABC Plumbing, LLC." This informs customers that the business is organized as an LLC and that the members' personal assets are protected by the business's liability-limiting structure.
Generally, a business's legal name includes the identifying phrase tacked onto the end to satisfy state law. As such, when a limited liability company business uses its name in advertising, it must use "LLC" along with the rest of its legal name. But not every logo uses the name of the business, so logos that use just an image in place of the name of the business generally do not have to use the "LLC" designation.