New 2021 W4

My boyfriend filled out the new w4 form 2021. 
we have never had to pay federal before. But currently it is saying he would owe over $1400! And he also has an extra $15 taken out weekly. 
I ‘think’ the problem is that he is listed as head of household with two exemptions. But I think the deduction portion may have been entered incorrectly. (The office lady does everything without any HR/payroll training ) so I think it is for my daughter plus me. But he cannot claim me. 
What is the best option to have on the new W 4 to not owe taxes? 
more is there a way to go back to the old w4.