Hi mhersol. Regarding the mailing labels, I just printed my mailing address on a bond paper, cut them about 4 in x 6 in, and placed double sided tapes at the back. I think you can also use printable sticker labels if you have them. When it comes to the envelope to be sent to CIO, the guide says we use a 9 in x 12 in envelope, which is equivalent to the short brown envelope available here. I followed the format in the Guide P7000 Step 4 - Mailing the Application. Note the difference in address if you will submit via regular mail or via courier. The green sticker naman, I just placed it at the upper right hand corner of the envelope. The instruction from MPNP is simply to "attach the green sticker label on the outside of the envelope." MPNP also says we must place the LOA on top of the application package, but I followed the CIO checklist which lists the LOA at number 11, right after the copies of passports. Hope this helps!