You can't, but you can set up a script in File Options to run every time that the file opens. That script can set the zoom to 200% for you automatically.
Thank you! That works perfectly! I now set the zoom to be 200% every time I open.
Did I just do the layout wrong when I made it? Why would I have to do this? Is it that one layout would be for viewing on screen and another for printing? If it is, that's a little crazy because I would simply want to print what is on my screen.
One layout for data entry and another for printing is often needed in database design. This is not unique to FileMaker as I often had to do that for MS Access when I was using that product.