Complex sentence: The Marrakech Agreement, manifested by the Marrakech Declaration, was an agreement signed in Marrakech, Morocco, on 15th April 1994, establishing the World Trade Organization, which officially came into being on January 1,1995.
Split into simpler sentences: The Marrakech Agreement was an agreement signed in Marrakech, Morocco, in 15th April 1994. The agreement established the World Trade Organization, which came into being upon its entry into force on January 1,1995.