Can you fold 1096 forms into a regular envelope before sending to the IRS?

Form 1096 is Annual Summary and Transmittal of U.S. Information Returns. It's a cover sheet that must accompany Forms 1099, 1098, 3921, 3922, 5498, and W-2G when they're being filed in paper form with the IRS. You must attach a separate 1096 form for each type of form that you're filing. For example, if you're submitting 5498 forms and W-2G forms, then you'd attach two 1096 forms as cover sheets, one for the 5498 group, one for the W-2G group.

Form 1096 isn't filed separately from its attachments. Transmitting to the IRS. According to the IRS website, "Send the forms in a flat mailing (not folded)." If you're filing any of the forms electronically, then you don't transmit Form 1096. Form 1096 is only used when you're sending paper forms to the IRS.