Okla. Stat. tit. 26, § 26-14-120: Marking, return, and processing of ballots

A. For ballots transmitted pursuant to the provisions of

Section 14-118 of this title, the voter shall be required to mark

the voter’s ballots in ink or other manner as prescribed by the

Secretary of the State Election Board, seal the ballots in the plain

opaque envelope, fill out completely and sign the affidavit, seal

the plain opaque envelope inside the envelope bearing the affidavit,

and return both envelopes, sealed inside the return envelope, by

United States mail or by a private mail service, provided such

service has delivery documentation.

B. If a voter returns both a voted ballot mailed to the voter

under subsection A of Section 14-118 of this title and a voted

ballot provided electronically to the voter under subsection B of

Section 14-118 of this title, only the first ballot received may be

counted.

C. A ballot received by the county election board which was

issued electronically shall be processed in the same manner as any

other ballot voted by mail as provided by this title.