The letter, return and payment record can answer different questions. Select support because it relates to the issue, preserving each source and its original context.
Explain why a record belongs
Start with the current notice and identify the point it raises. Choose another source because it helps with that point, retaining its period and what it actually shows. An earlier payment reference may explain a transaction while leaving account treatment uncertain. Keep that gap as a question. A useful file has understandable relationships rather than giving every nearby document equal importance merely because it was collected at the same time.
Preserve originals and useful follow-up
Keep source material unchanged and add later explanation separately with its date. Ask which further evidence the proposed review needs and how sensitive copies should be delivered. Understand work, charges and authority before proceeding. A purposeful next information request can make assistance useful while older details remain unavailable, avoiding a reconstructed account story or the assumption that assembling a packet itself submits a formal IRS response.