Creating a new blank canvas - Studio

I want to start off with a blank canvas (800x2000 pixels - for Pinterest) onto which I can place text and photos. Can’t seem to find out how to do this?

If you’re asking about creating one from scratch in Studio I don’t think you can. You could import an all white image from Photoshop and use that, or you could use one of your own images that is the correct size and apply a colour (white) at 100%, Apply or Save, and use that as your base.