Depending on your child's income, they may not even need to file a return.
https://ttlc.intuit.com/questions/1901490-do-i-need-to-file-a-federal-return-this-year?jump_to=answe...
https://turbotax.intuit.com/tax-tools/tax-tips/IRS-Tax-Return/Does-Everyone-Need-to-File-an-Income-T...
