Okla. Admin. Code § 710:65-21-3
All purchases of tangible personal property which are purchased in a manner such that, pursuant to OAC710:65-15-1, sales tax is not due, but which are stored, used or otherwise consumed in Oklahoma are subject to the use tax. The use tax must be remitted directly to the Commission by the vendor, if the vendor is either "maintaining a place of business in this state", as defined by OAC710:65-1-8, and has knowledge that the goods are being sold for use in this state; or if the vendor is not "maintaining a place of business in this state", but has voluntarily agreed to collect Oklahoma Use Tax. In the event that the vendor is not "maintaining a place of business in this state" and has not voluntarily agreed to collect the use tax, the Oklahoma purchaser must accrue, report, and remit the use tax.
Okla. Admin. Code § 710:65-21-3