A family of Microsoft word processing software products for creating web, email, and print documents.
Create a canvas of the size that you want. Them, with it selected, click on File then Options then Proofing then AutoCorrect Options and in the Replace with box type dcanvas then click the Formatted text radio button if it is not selected and then click on the Add button and then on OK and OK again.
Then, whenever you want that size drawing canvas, type dcanvas and press Enter.