Mailing labels are a required part of the employment visa application.
You are required to provide a mailing label "to" USCIS. You are strongly encouraged to provide a mailing label to "return" approval notices from USCIS. You should use FedEx which provides drop boxes on the Stanford campus.
Courier Services—Mailing Label Guidelines
You must provide electronically-generated, pre-printed, pre-paid mailing labels that you create using your account as the billing account.
Regular Processing Courier Address
USCIS, Vermont Service Center
ATTN: I-129 TN Processing (You should enter "E-3" if that is that is the appropriate visa)
75 Lower Weldon St.
St. Albans,VT 0579-0001
800-375-5283
Premium Processing Courier Address (TN visas only, not available for E-3)
Premium Processing Service
USCIS Vermont Service Center
ATTN: I-129 TN Processing
30 Houghton Street
St. Albans. VT 05478-2399
800-375-5283
Return Mail
If you would like the approval notice to be returned by express courier, please include a return mailing label with the address of Bechtel International Center:
H-1/TN Unit
Bechtel International Center
Stanford University
584 Capistrano Way
Stanford, CA 94305
650.725.7400
In the "sender" area of the return mailing label please use your departmental address. Do not use the USCIS address in the sender field—this will cause your application to be rejected.