If i paid my 17 year old son 12000 last year as a 1099 employee where do i deduct that on my taxes?

Enter the payment as Contract Labor expenses in the Self-Employment section for expenses on Schedule C.

That is Contract Labor Schedule C line 11. Are you doing a 2022 return or asking about 2023?  To do a 2022 return you need to use the Desktop installed program.  The 2023 Online version hasn't opened yet.   And he will need to file his own return as a dependent to file it as his own self employment on schedule C and pay SE tax on it.  The Desktop program can do more than 1 return.  Be sure on his return he checks the box that says he can be claimed on someone else's return.