for my assignment we are pretending that we are going somewhere in the world.we're pretending to write to a travel agent about the place we are going to.

here's the sample:
Title:________________________
Address:____________________________
City,State,Zip:________________________

what should i write for title.
i don't understand.

You are to write a business letter. There is no title.

http://owl.english.purdue.edu/owl/resource/653/01/

Read all about business letters here and study the sample letter. Then write yours.

For the title of your letter to the travel agent, you can typically use something like "Inquiry for a Trip" or "Request for Travel Information." The title is meant to provide a brief indication of the purpose of your letter. It should be clear and concise so that the travel agent can easily understand what you are seeking assistance with.