ظرف بريدي

thumb|upright=1.35|alt=Front of an envelope mailed in the U.S. in 1906, with a postage stamp and address|Front of an envelope mailed in the U.S. in 1906, with a postage stamp and address thumb|upright=1.35|alt=Back of the above envelope, showing an additional receiving office postmark|Back of the above envelope, showing an additional receiving post office [[postmark]]