Editing Postmark (section)

== Practical uses ==
The postmark is often considered as an official confirmation that a cover (letter, packet, etc.) mailed item was mailed at a given location at a specific date. For example, the date of the postmark can be quite important. In the United States, the [[Internal Revenue Service]] will still consider [[income tax]] returns as filed on time though it receives them late if they are postmarked on time, and this date (with, perhaps, other [[Registered mail|proof of mailing]]), may have significance in the context of legal filings and [[Proof of service|proofs of service]] or [[Proof of delivery|of delivery]] (though in this case the date may viewed as "on time" if the date of the postmark is no more than one day after the date service is supposed to have been made).<ref>Examples from ''[[Church of Scientology International v. Fishman and Geertz]]'', a civil case before the U.S. District Court for the Central District of California: {{cite web |url= https://www.cs.cmu.edu/~dst/Fishman/Declaration/venserv.html |title=Proof of Service |first=Robert A. |last=Weiner |publisher=Bowles & Moxon |location=Los Angeles |via=CS.CMU.edu |date=April 9, 1993 |access-date=February 22, 2009}}</ref> [[Postal voting|Postal voting ballots]] may be accepted in some places if postmarked by the date of the election, though other places require receipt by a certain deadline. Historically, postmarks, known as [[backstamp]]s were also applied to the reverse side of a cover to confirm arrival at the post office on a specific date.<ref>{{cite web |title=Mute oval canceling device handstamp |work=PostalMuseum.SI.edu |publisher=[[National Postal Museum]], [[Smithsonian Institution]] |location=Washington DC |date=18 April 2006 |url= https://postalmuseum.si.edu/object/npm_1992.2002.152 |id=GUID ark:/65665/hm83cefd3104acf435d94356e84f94f42dd |access-date=30 July 2020}}</ref>