Your paper is set to Letter size as is most common. You might be able to select Custom in the drop down or you might have to click on Options to get to a Custom Paper size dialog.
The election machine makers have many models of machines and versions of software for different purposes. Touch screens and the apps for it. Ballot designer apps for ballot printers etc. One would have to know what Maricopa uses and get access to the operation manual for it to know what can and can't be done, how print size is changed etc.
Certified Systems - https://www.eac.gov/voting-equipment/certified-voting-systems
I think all of the above are what States/Counties get to choose from though it's possible they could choose their own system.