I submitted my 2023 taxes this year instead of last year. I need my AGI number for my identity on my 2024 tax return. I have the reference copy, can I use the AGI number?

Yes, you use the AGI from 2023 on your 2024 tax return.

Refer to the TurboTax help article How to Find Your Adjusted Gross Income (AGI) to E-file Your Tax Return

When did you file 2023?  Did you mail it?  If you used the Online version this year to do your 2023 return that was wrong.   Online is only good for 2024.

If you filed 2023 late or mailed it then use 0 for the AGI to efile 2024.   The IRS won’t have it in the right database to verify you for  2024.