OMB stands for Office of Management and Budget. It is not part of a Form 1099 other then used as a form number such as 1545-0115
We need to know which of the almost two dozen different type of Form 1099 you are referring to:
Form 1099-A, Acquisition or Abandonment of Secured Property
Form 1099-B, Proceeds From Broker and Barter Exchange Transactions
Form 1099-C, Cancellation of Debt
Form 1099-CAP, Changes in Corporate Control and Capital Structure
Form 1099-DIV, Dividends and Distributions
Form 1099-G, Certain Government Payments
Form 1099-H, Health Coverage Tax Credit (HCTC) Advance Payments
Form 1099-INT, Interest Income
Form 1099-K, Payment Card and Third Party Network Transactions
Form 1099-LTC, Long-Term Care and Accelerated Death Benefits
Form 1099-MISC, Miscellaneous Income
Form 1099-NEC, Nonemployee Compensation
Form 1099-OID, Original Issue Discount
Form 1099-PATR, Taxable Distributions Received From Cooperatives
Form 1099-Q, Payments From Qualified Education Programs (Under Sections 529 and 530)
Form 1099-R, Distributions From Pensions, Annuities, Retirement or Profit-Sharing Plans, IRAs, Insurance Contracts, etc.
Form 1099-S, Proceeds From Real Estate Transactions
Form 1099-SA, Distributions From an HSA, Archer MSA, or Medicare+Choice MSA