Front page marking:
If a document contains OUO, the front page must have the front marking. (DOE M 471.3-1, Admin Chg 1, Chapter I, Paragraph 3a.)
For instructions on filling out the front marking and an electronic sample you may copy to a document, see OUO Stamp with Directions.
The marking "OFFICIAL USE ONLY" must be placed on the bottom of the front of the document and on the bottom of each interior page of the document that contains text or if more convenient, on the bottom of only those interior pages that contain OUO. If space limitations do not allow for use of the full page marking, the acronym "OUO" may be used as the page marking. (DOE M 471.3-1, Admin Chg 1, Chapter I, Paragraph 3b.)
A document that transmits documents or material marked as containing OUO and does not itself contain classified information or OUO must be marked on its front with "Document(s) transmitted contain(s) OUO information". (DOE M 471.3-1, Admin Chg 1, Chapter I, 3f.)
If the e-mail contains OUO information, the first line of an e-mail message must contain the abbreviation "OUO." There is no requirement to detail all of the information that is required in the front marking for hard copies (e.g., exemption name and number or guidance used, if applicable.) If the e-mail itself does not contain OUO, but an attachment contains OUO, the message must indicate the attachment is OUO (there is no specific language required.) (DOE M 471.3-1, Admin Chg 1, Chapter I, 3c.)
See DOE M 471.3-1, Admin Chg 1, Chapter I, paragraph 3, for marking instructions. For samples of the above markings and others, see Marking OUO Documents.