When you need to apostille an Oklahoma birth certificate, you will need to make sure to have a certified copy of the vital record beforehand. If you need to order one, your best bet is to go through the Oklahoma State Department of Health. Here's what their website says about obtaining one:
Please contact the Court Clerk in the county of the event.
Apostille for Oklahoma Marriage Certificate
There is no margin for error with the Authentication or Apostille process. If mistakes are made, both your time and money will be wasted and you'll have to start all over again. If you want to look into outsourcing this part of preparing to studying abroad to someone with experience, please email me at email@example.com or call 848-467-7740 to request my services or learn more.