Keep the gift instruction and payment confirmation with the earlier USCIS correspondence and I-140G materials. Follow any further request as written. For consular processing, the interview instructions identify civil documents, police certificates, medical requirements and other evidence; do not assume the gift letter replaces that list. Every document has a body that issues it and a body that accepts it, and neither is you. A civil registrar issues the record; a translator attests the translation; the post specifies the form in which it will accept both. Confirm those requirements from the instruction governing your own case rather than from another applicant's experience.
Filing responses through the official portal without breaking the record
Use the submission channel named in each actual request. The USCIS portal stage and a consular document procedure may differ, so a blanket rule against email, courier or originals would be unreliable. Retain receipts and identify each item clearly.
If a required record is unavailable, review the applicable instructions for explaining its absence and acceptable alternative evidence rather than inventing a substitute. Hypothetical example: an applicant who has run a marine engine service business abroad assumes the corporate records that satisfied a bank will satisfy the consular stage. The interview instructions call instead for personal civil documents and police certificates from each country of residence over a defined period.
Recognising the difference early, the applicant orders the slowest certificates first and treats the company paperwork as a separate file.