How can I obtain a non-immigrant Visa O-A for my spouse under 50 years old as a dependent?

To obtain a Non-Immigrant Visa O-A for your spouse under 50 years old, you cannot apply directly for them. Instead, you should apply for the Non-OA visa for yourself. Following your successful application, your spouse can then apply for a Non-O dependent visa based on your status. This process provides a 90-day initial entry, after which an extension can be obtained at an immigration office.