We are in the process of adoption

If the child was legally placed with you pending adoption, and you can at least get an adoption taxpayer ID number or an Individual taxpayer ID number by the due date of your return, then you may qualify for the Credit for Other Dependent. For the Child Tax Credit, you would needs a Social Security Number.

This IRS webpage includes an answer to a situation like yours:

As a prospective adoptive parent in the process of adopting a U.S. citizen or resident, you'll need a taxpayer identifying number (TIN) for the child who is being adopted to claim the child as a dependent. If you don't have and are unable to obtain the child's Social Security number (SSN), you should request an adoption taxpayer identification number (ATIN) or individual taxpayer identification number (ITIN). Please note that an ATIN will expire 2 years after the date of issue.

• An ATIN is available if a child who is a U.S. citizen or resident is lawfully placed in your household for legal adoption. To obtain an ATIN, use Form W-7A, Application for Taxpayer Identification Number for Pending U.S. Adoptions. For more information, refer to the Instructions for Form W-7A PDF PDF and to Adoption taxpayer identification number.
• If the child isn't a U.S. citizen or resident, and if the child qualifies as a dependent, a TIN is still required. To obtain an ITIN, use Form W-7, Application for IRS Individual Taxpayer Identification Number. For more information, refer to Individual taxpayer identification number.

Please note that you may not claim the child tax credit on either your original or an amended return if your child doesn't have an SSN valid for employment before the due date of your return (including extensions). If your child has an ATIN or an ITIN, your child may qualify you for the credit for other dependents.