When NIH transitions from one form set to another, it is your application’s targeted due date that determines which form set you should use, rather than the literal date of submission.
FORMS-H goes into effect for applications due on or after January 25, 2023. For most investigators, that means the time to switch to FORMS-H has already arrived. However, there are exceptions. For example, if you are eligible for continuous submission and were targeting the January 7, 2023 due date for AIDS-related R01 applications (in which case you have until February 1, 2023, to submit your application), you should use the FORMS-G application package.
For further assistance, refer to NIH’s High-level Summary of Form Changes in FORMS-H Application Packages and Do I Have the Right Forms for My Application? instructions.