I'm bamboozled by these first two, what era? They're Australian and the third one I bought from an Austrian eBayer called Dr Zettel a few years ago. The 'golden records' logo is a knock-off of the London Underground logo, I remember the 'purple people eater' from the early 1960s . . . maybe?
So these are for posting through the mail . . . the third one is similar to the back of a postcard, ruled lines for an address and postage stamp.
The first two have an area with To: and Best Wishes From: