Structural Design patterns in C#

I have a task to create a simple program for sending postcards. Every postcard contains title, body and address. Program need to provide predefine messages in the body of postcard and creating a new postcards without changing the class code. One postcard can be send to many users. In the body of it, there should be a option to add an image. My question is which of the structural patterns (Adapter, Bridge, Decorator, Facade, Composite, Proxy, Flyweight) should I use for solving this problem. Thank you in advance!