Im a us citizen but i was living in mexico and i got married over there and we have 3 kids in mexico, how can i add them to my taxes if they dont have ssn or itin .

In order to claim them on your taxes, you would need to apply for an ITIN for them. 

Without an SSN or ITIN, you won't be able to e-file either.   You would need to submit your taxes and apply for ITIN simultaneously with TurboTax program:

-In the program, as you enter the information, leave the SSN space blank

-After entering all your information, print out returns and required forms ( write APPLIED in the SSN space) 

-As TurboTax does not support the Form W-7, fill out the forms by following

 https://www.irs.gov/Individuals/General-ITIN-Information and attach to other required  documentation

-Submit everything including your tax forms to IRS Austin location in Texas.  ( Form W-7 instructions)

Please note that, for some tax benefits, for example, the Earned Income Credit EIN or the Child Tax Credit, they must have an SSN in order for you to claim.