Child deduction

How do I find out if I was supposed to get more money for my daughter from previous years? I got 2k when I filed 2019, but when I filed 2017 and 2015, I only received 1k.

 

Do I need to complete a form?

 

Thank you in advance!

Deductions & credits

The amount of the Child Tax Credit was increased in 2018 so there is nothing to correct. 

Deductions & credits

Thank you Critter.