Yes. You can claim HOH and give him the dependency. You will need Form 8332. When you go thorough the Personal Info section, you will see the questions that lead you to the form.
The screens can be tricky. Basically, if the question applies to residence, it pertains to Head of Household. You have to indicate that you are allowing the other parent to claim the exemption.
Dependency Questions:
What's Megan's relationship to you?
We know Megan is_, but we have to ask: Did she pay for most of her living expenses?
Do you have an agreement with Megan's other parent about who can claim her?
Is Megan's other parent claiming Megan per your legal agreement?
Are you letting Megan's other parent claim Megan for 2018?
Head of Household Questions:
What's Megan's relationship to you?
How many months did Megan live with you in 2018?
Where did Megan spend the most nights in 2018?
Did a relative live in your home and help support Megan?
