uh. how do you make the box thingy?

) i don't know how to explain. i'm so new at all of this.
i think its where you put the really long code. so that it's easier to access.? i don't know how. i think? haha. pls teach me?

can you actually make that? coz i want to put it in my multiply, in the guestbook part. so it'll be easier. hope this isn't too confusing. sorry. i just really wanted to know how to do that.

thanks if this will be answered