The under word is used when you want to say something that is under and covered by other objects. This word is always followed by a noun. To be more clear, let's look at the example below :Your shoes are under the table – The word below is used when you want to say something that is down and has a distance. What is meant by the distance here is when the object being talked is not directly under another object. As an example:Johnny’s apartment is below Jessica’s