If only the $500 Credit for Other Dependent populated on your return, rather than the Child Tax Credit, then it is likely your child is aged 17 or older. The $500 Credit for Other Dependents was signed into law as part of the 2017 Tax Cuts and Jobs Act and is in effect for tax years 2018 through 2025. The credit allows taxpayers a credit for certain dependents that don't qualify for the Child Tax Credit, such as qualifying children age 17 or older, adult dependents, and dependents who have an ITIN.

Please see Intuit What is the $500 Credit for Other Dependents (“Family Tax Credit”)? for more information. 

Why am I getting the Credit for Other Dependents instead of the Child Tax Credit?

 My children are 3 and 5 years old.  Neither are over 17 years of age.  How do I correct the tax return?

First do not amend any return until the IRS fully processes the original return AND you  have the original refund in hand.  

Then start the amendment process and review/edit the kids in the MY INFO section since you must have made a data entry error in that section.