[header] How to claim a child tax credit [title] Make sure you qualify to use this form. [step] If your child has an individual tax identification number instead of a social security number, you must use schedule 8812. If you're claiming certain other credits such as the adoption credit or mortgage interest credit, you need to use publication 972. 
All other taxpayers use the worksheet accompanying form 1040 or form 1040a. [title] Enter the number of qualifying children you have on the first line.