IRS Tax Tip 2018-182  discusses the new child tax credit rules. 

Bottom line is that more people should get the full $2,000 credit per child as the income threshhold has increased to $200,000 single and $400,000 married filing jointly.  There is a dependent credit of $500 per person that does not fall under the “child” rules.

The full IRS tax tip can be read at:

https://www.irs.gov/newsroom/whats-new-with-the-child-tax-credit-after-tax-reform