An envelope with integrated tracking labels for forwarding on important documents where proof of delivery and reception is required is described herein. The envelope has a securing flap which is provided with a receipt tear panel formed in a free end section of the flap and provided with a tracking number printed thereon. A glue strip extends longitudinally across an inner face of the securing flap. A release liner is removably retained over the glue strip. A tracking label having the same tracking number is die-cut in the securing flap over the release liner. The release liner is scored to form a tracking label release liner section adhered to the glue strip about the tracking label whereby to retain the tracking label in the securing flap. The glue strip secures the securing flap to an edge section of the other panel when folded thereon on the fold line. The tracking number is also printed on one of the panels. The tracking label is removed from the tracking label release liner of the securing flap as proof of sending or reception of the envelope.