To claim my baby born in sept how to claim the vhild tax credit and do i mail all the paper work when amending this or just the 1040x part

[Vanessa]

When you enter your baby, you will simply select that he or she lived with you for all 12 months/The Whole Year even though they were born in September.  After you enter all of their information, proceed through the interview and when you come to Deductions and Credits walk through all of the credits.  You will come to one for the Child Tax Credit and also if you qualify one for the Earned Income Tax Credit.  

If you have all of the information entered already for your child (including that they lived with you for the entire year) you can also just click on Federal>>>Deductions and Credits>>Scroll down and click Show More next to You and Your Family>>>then click start next to Child Tax Credit