VERIFIED SOLUTION i

How to use A3 as aDOC1 Output

In general Doc1 can produce output for any page size supported by the device in question. The paper format can be set in the individual devices:
User-added image

To actually format the output for a different logical page size, the "paper size" setting in the document editor would also need to be set. This setting is in the Page Setup in the document editor.

While there is no preset for A3 there is a "User defined size" which can be used to format the output for the appropriate size:

User-added image
Environment Details
Product Feature: Document Editor
UPDATED:  November 7, 2017