Have a look on the Fairtrade website to find out what it is and what it does.
https://www.fairtrade.org.uk/What-is-Fairtrade
Fairtrade means that the worker will be provided with enough money to cover their basic living costs. Often, this means that the prices of these products in the shops will be slightly higher than others. Fairtrade also gives groups of workers a 'Fairtrade Premium' which means that they can invest it in things that will help them. For example, in training others to do the same job or building houses.
Look at the map to see in which countries Fairtrade supports farmers:
http://www.fairtrade.org.uk/What-is-Fairtrade/Where-Fairtrade-works
Then, watch this short film about Foncho, who is a banana grower. How has Fairtrade helped him?
https://schools.fairtrade.org.uk/resource/make-bananas-fair-a-film-for-schools/
Now have a go at designing a poster for a Fairtrade product. Usually these products are slightly more expensive to ensure the farmer gets a fair price. Can you convince people in shops to buy a Fairtrade product?