Does anyone know why I got a 1099 G form for 2024 but the taxable year is 2023. Plus I already filed and then this shows up in my mail box. I never was on unemployment.

Did you receive a state or local tax refund for 2023?    The state or local government send out a 1099G for that.

IS MY 2023 STATE OR LOCAL REFUND TAXABLE?

If you used standard deduction for your 2023 tax return, you do not have to enter a state or local tax refund you received in 2024.   If you itemized deductions then your state or local refund that you claimed on the 2023 return----and received in 2024---must be entered as taxable income on your 2024 return.  If you  are not sure if you itemized for 2023, look at your 2023 Form 1040 line 12.   Do you see the standard deduction amount or something else?

2023 STANDARD DEDUCTION AMOUNTS

SINGLE $13,850  (65 or older/legally blind + $1850)

MARRIED FILING SEPARATELY $13,850  (65 or older/legally blind + $1500)

MARRIED FILING JOINTLY $27,700  (65+/legally blind) )  + $1500 per spouse

HEAD OF HOUSEHOLD  $20,800 (65 or older/blind)  + $1850)

Is an amount entered in box 1 of the Form 1099-G?  If so, that is for unemployment compensation and if you never were unemployed or never received unemployment compensation then you need to contact your state to get this corrected.  The Form 1099-G is also sent to the IRS so they would expect to see this unemployment on your tax return.

Is tax year 2023 noted in the box labeled For calendar year?