People use persuasive writing to try and convince the reader that their point of view on a subject is right, or that someone else's point of view is wrong.
The main goal is often to persuade someone to do something you want them to. It might be that you are trying to convince people to agree with your opinion, or buy your product.
One way to try and convince someone to agree with your point of view is to write a letter. A persuasive letter should give reasons to support your cause and should contain an argument explaining why you believe you are right, and perhaps what the consequences will be if the reader does not support your ideas.
Adverts are the most common form of persuasive writing you'll find on TV, on websites, in magazines, newspapers, leaflets and on notice boards. People use this kind of writing - and usually some very persuasive graphics - to encourage you to buy things.