What is the box 1120-C filer used for in the client information section

[Kathi_at_Intuit]

Thank you for stopping by the community and posting your first questions. In Lacerte, if you were to check off the box 1120-C Filer? and type F1, this would bring you up the in product help and show you this information:

1120-C Filer?
Federal Client Information

This entry is mandatory to generate Form 1120-C. Select the box if you are processing a return for a cooperative association and are required to file Form 1120-C. Otherwise, leave this field blank.

In addition, California returns may now be filed electronically if the Federal return has Form 1120-C. The federal return must be attached as a PDF to the California Electronic return.

Here are the instructions for the 1120-C Filer, I would also look under Who Must File sections:

https://www.irs.gov/instructions/i1120c#idm140069323693072