You can leave a message on a processing document if you use a string command.
println(“The currency of the UK is the pound”). Setting a size and background will cause a separate screen to show and display the message in the println on the original document.
This video shows you about the User Interface in Processing, the menus are along the top of the document where you can use find in reference to search for how to enter a certain command. You can manually pick a colour in Tools>Colour Selector, this involves the RGB colour scheme.
text(“Hello”, 0, 20);
text(“Goodbye”, 0, 40)
The good thing about this is that you can type out as many words as you please.