Something that's fabricated is faked or invented, like a fabricated story about how the dog ate your homework. Trust us, no one believes that.
If a journalist uses fabricated quotes, it means he made them up, and if a police officer uses fabricated evidence, it means she deliberately planted or falsified it. Some fabricated things are literally manufactured, like the fabricated parts used to build a car. Both senses of this adjective come from the verb fabricate, "construct" or "make," and share a root with fabric that means "fit together."