The IRS does not require this mechanism, but it allows the most flexibility among the beneficiaries and all required information reporting will be generated automatically.
Set up a "payout" account in the name of each beneficiary; e.g. Jane Smith, beneficiary John Smith IRA. (The wording is not negotiable.) The payout account will use the beneficiary's address and SSN. Each beneficiary has a right to name their own beneficiary on their payout account, but need not execute an IRA agreement. (Jane is not opening an IRA, she is taking a payout from John's IRA.)
1)Transfer the appropriate pro rata portion from John's IRA to that of each beneficiary; e.g. if there were 4 beneficiaries, transfer 1/4 of the amount from the decedent's IRA to Jane's payout account. This is an "internal" transfer, it is not a reportable transaction.
2) Let each beneficiary chose the payout option they wish for his or her account; e.g. they can take it all in a heated rush, spread it over their life expectancy, etc. There are some requirements. (This account is not eligible to receive contributions; it's sole purpose is to facilitate the proper distribution and reporting of the amounts involved.) Your forms vendor would appreciate it if you required each beneficiary to sign a form indicating their distribution and withholding preferences, but it may or may not be necessary. (Generally, this only needs to be done once.)
3) All distributions from the beneficiaries' payout accounts are reportable with a distribution code of "4," i.e. a distribution due to death.
These are not "Oklahoma" specific questions and might have a better chance of being noticed in the "general" forums; e.g. Operations.
In this world you must be oh so smart or oh so pleasant. Well, for years I was smart. I recommend pleasant.