Are the details of your sell transactions itemized on your Form 8949 that you e-Filed?
If YES, you don't have to mail the form(s) in on paper.
If the form 8949 you e-Filed says "see attached". it is a summary 8949 not a detail 8949.
IRS requires the details.
If you e-File without the details,
you can mail a paper form 8949 with the details, or some other form with the details that has the information in the same manner as Form 8949. the consolidated 1099-B from your broker, for example, is acceptable.
@rnhardin
