If you are trying to communicate with a Spanish speaker in the U.S. or Latin America you will not need to translate the term Marketing. Most Spanish speakers understand the word marketing and it is sometimes used more than the actual equivalent word in spanish. However, I have create this simple guide of how to use the different terms for marketing in spanish with its own definition in english that you can use in your conversation or content.
Mercadeo: All the operations by which a commodity has to pass from producer to consumer.
Mercadotecnia: Set of principles and practices that seek increased trade, especially in demand.
Mercadear: Make deal or trade in goods.
This is an example how you can use the word!
Spanish Sentence: Las mejores técnicas de mercadeo para este año
Meaning in English: The best marketing techniques for this year